diff --git a/docs/bootstrap-inventory.md b/docs/bootstrap-inventory.md
index b937e8914..1d9bd0e4f 100644
--- a/docs/bootstrap-inventory.md
+++ b/docs/bootstrap-inventory.md
@@ -8,11 +8,11 @@ Regenerate: `php script/bootstrap-inventory.php`
 
 | Metric | Count |
 |--------|------:|
-| PHP files on vm.php path | 4311 |
-| Phase A inventory files (M2 ratio SSOT) | 4311 |
+| PHP files on vm.php path | 4312 |
+| Phase A inventory files (M2 ratio SSOT) | 4312 |
 | Phase A ratio-deferred paths | 0 |
 | Source constructs flagged (blockers) | 0 |
-| Source constructs flagged (warnings) | 11621 |
+| Source constructs flagged (warnings) | 11622 |
 
 ## Compiler CFG gaps (`lib/Compiler.php`)
 
@@ -56,6 +56,7 @@ Rank live CFG gaps across inventory files: `php script/bootstrap-inventory-triag
 | `ext/bcmath/bcscale.php` | 0 | 1 |
 | `ext/bcmath/bcsqrt.php` | 0 | 1 |
 | `ext/bcmath/bcsub.php` | 0 | 1 |
+| `ext/brotli/BrotliExtensionPolicy.php` | 0 | 1 |
 | `ext/brotli/BrotliJitHelper.php` | 0 | 1 |
 | `ext/brotli/JitBrotli.php` | 0 | 1 |
 | `ext/brotli/Module.php` | 0 | 3 |
@@ -4438,6 +4439,11 @@ Rank live CFG gaps across inventory files: `php script/bootstrap-inventory-triag
 **Warnings** (review for bootstrap subset):
 - 1 class method(s)
 
+### `ext/brotli/BrotliExtensionPolicy.php`
+
+**Warnings** (review for bootstrap subset):
+- 1 class method(s)
+
 ### `ext/brotli/BrotliJitHelper.php`
 
 **Warnings** (review for bootstrap subset):
@@ -4451,8 +4457,8 @@ Rank live CFG gaps across inventory files: `php script/bootstrap-inventory-triag
 ### `ext/brotli/Module.php`
 
 **Warnings** (review for bootstrap subset):
-- new brotli_compress (line 21)
-- new brotli_uncompress (line 22)
+- new brotli_compress (line 24)
+- new brotli_uncompress (line 25)
 - 1 class method(s)
 
 ### `ext/brotli/VmBrotliNative.php`
@@ -5786,48 +5792,48 @@ Rank live CFG gaps across inventory files: `php script/bootstrap-inventory-triag
 - new DomNodeState (line 2414)
 - new DOMException (line 2561)
 - new DOMException (line 2575)
-- new Variable (line 2589)
-- new DOMException (line 2603)
-- new DOMException (line 2606)
-- new DOMException (line 2614)
-- new DOMException (line 2640)
-- new DOMException (line 2653)
-- new DOMException (line 2839)
-- new DOMException (line 3036)
-- new DOMException (line 3040)
-- new DOMException (line 3129)
-- new DOMException (line 3133)
-- new DOMException (line 3191)
-- new DOMException (line 3208)
-- new DOMException (line 3237)
-- new DOMException (line 3278)
-- new DOMException (line 3303)
-- new DOMException (line 3789)
-- new Variable (line 3813)
-- new DOMException (line 4036)
-- new DOMException (line 4117)
-- new DOMException (line 4159)
-- new ObjectEntry (line 4244)
-- new DomNodeState (line 4248)
-- new Variable (line 4255)
-- new ObjectEntry (line 4455)
-- new DomNodeState (line 4459)
-- new Variable (line 4466)
-- new ObjectEntry (line 4486)
-- new DomNodeState (line 4489)
-- new Variable (line 4497)
-- new DOMException (line 4699)
-- new DOMException (line 4706)
-- new DOMException (line 4713)
-- new DOMException (line 4717)
-- new DOMException (line 4720)
-- new DOMException (line 4729)
-- new Variable (line 5477)
-- new Variable (line 5490)
-- new DOMException (line 5572)
-- new DOMException (line 5583)
-- new DOMException (line 5649)
-- new DOMException (line 5657)
+- new Variable (line 2591)
+- new DOMException (line 2605)
+- new DOMException (line 2608)
+- new DOMException (line 2616)
+- new DOMException (line 2642)
+- new DOMException (line 2655)
+- new DOMException (line 2841)
+- new DOMException (line 3038)
+- new DOMException (line 3042)
+- new DOMException (line 3131)
+- new DOMException (line 3135)
+- new DOMException (line 3193)
+- new DOMException (line 3210)
+- new DOMException (line 3239)
+- new DOMException (line 3280)
+- new DOMException (line 3305)
+- new DOMException (line 3791)
+- new Variable (line 3815)
+- new DOMException (line 4038)
+- new DOMException (line 4119)
+- new DOMException (line 4161)
+- new ObjectEntry (line 4246)
+- new DomNodeState (line 4250)
+- new Variable (line 4257)
+- new ObjectEntry (line 4457)
+- new DomNodeState (line 4461)
+- new Variable (line 4468)
+- new ObjectEntry (line 4488)
+- new DomNodeState (line 4491)
+- new Variable (line 4499)
+- new DOMException (line 4701)
+- new DOMException (line 4708)
+- new DOMException (line 4715)
+- new DOMException (line 4719)
+- new DOMException (line 4722)
+- new DOMException (line 4731)
+- new Variable (line 5481)
+- new Variable (line 5494)
+- new DOMException (line 5576)
+- new DOMException (line 5587)
+- new DOMException (line 5653)
+- new DOMException (line 5661)
 - 277 class method(s)
 - 2 closure(s)
 
@@ -22569,45 +22575,45 @@ Rank live CFG gaps across inventory files: `php script/bootstrap-inventory-triag
 - new OpCode (line 37435)
 - new OpCode (line 37467)
 - new OpCode (line 37529)
-- new Operand\Temporary (line 39209)
-- new Operand\Temporary (line 39702)
-- new Operand\Temporary (line 39888)
-- new Operand\Temporary (line 39920)
-- new Operand\Temporary (line 40016)
-- new Operand\Temporary (line 40138)
-- new OpCode (line 40140)
-- new OpCode (line 41518)
-- new Operand\Temporary (line 41976)
-- new OpCode (line 42500)
-- new Operand\Literal (line 42799)
-- new Variable (line 42801)
-- new OpCode (line 42847)
-- new OpCode (line 43062)
-- new OpCode (line 43072)
-- new OpCode (line 43075)
-- new Operand\Temporary (line 43102)
-- new Operand\Temporary (line 43139)
-- new OpCode (line 43141)
-- new OpCode (line 43152)
-- new Operand\Temporary (line 43155)
-- new OpCode (line 43157)
+- new Operand\Temporary (line 39217)
+- new Operand\Temporary (line 39710)
+- new Operand\Temporary (line 39896)
+- new Operand\Temporary (line 39928)
+- new Operand\Temporary (line 40024)
+- new Operand\Temporary (line 40146)
+- new OpCode (line 40148)
+- new OpCode (line 41526)
+- new Operand\Temporary (line 41984)
+- new OpCode (line 42508)
+- new Operand\Literal (line 42807)
+- new Variable (line 42809)
+- new OpCode (line 42855)
+- new OpCode (line 43070)
+- new OpCode (line 43080)
+- new OpCode (line 43083)
+- new Operand\Temporary (line 43110)
+- new Operand\Temporary (line 43147)
+- new OpCode (line 43149)
+- new OpCode (line 43160)
+- new Operand\Temporary (line 43163)
 - new OpCode (line 43165)
 - new OpCode (line 43173)
 - new OpCode (line 43181)
-- new OpCode (line 43184)
-- new OpCode (line 43212)
-- new OpCode (line 43235)
-- new OpCode (line 43252)
-- new OpCode (line 43259)
-- new Operand\Literal (line 43938)
-- new OpCode (line 45063)
-- new Literal (line 45095)
-- new OpCode (line 45194)
-- new Variable (line 45201)
-- new Temporary (line 45203)
+- new OpCode (line 43189)
+- new OpCode (line 43192)
+- new OpCode (line 43220)
+- new OpCode (line 43243)
+- new OpCode (line 43260)
+- new OpCode (line 43267)
+- new Operand\Literal (line 43946)
+- new OpCode (line 45075)
+- new Literal (line 45107)
 - new OpCode (line 45206)
-- new CompileFatal (line 45541)
-- new CompileFatal (line 45796)
+- new Variable (line 45213)
+- new Temporary (line 45215)
+- new OpCode (line 45218)
+- new CompileFatal (line 45553)
+- new CompileFatal (line 45808)
 - 962 class method(s)
 - 47 closure(s)
 
@@ -22960,7 +22966,7 @@ Rank live CFG gaps across inventory files: `php script/bootstrap-inventory-triag
 ### `lib/CompilerVersion.php`
 
 **Warnings** (review for bootstrap subset):
-- 166 class method(s)
+- 167 class method(s)
 
 ### `lib/CurlyBraceOffsetRejector.php`
 
diff --git a/docs/bootstrap-profile.json b/docs/bootstrap-profile.json
index e25ba963a..769b3f739 100644
--- a/docs/bootstrap-profile.json
+++ b/docs/bootstrap-profile.json
@@ -43,6 +43,7 @@
         "ext/bcmath/bcscale.php",
         "ext/bcmath/bcsqrt.php",
         "ext/bcmath/bcsub.php",
+        "ext/brotli/BrotliExtensionPolicy.php",
         "ext/brotli/BrotliJitHelper.php",
         "ext/brotli/JitBrotli.php",
         "ext/brotli/Module.php",
@@ -245,6 +246,8 @@
         "ext/dom/NodeReplaceChild.php",
         "ext/dom/NodeReplaceChildren.php",
         "ext/dom/NodeReplaceWith.php",
+        "ext/dom/TextIsElementContentWhitespace.php",
+        "ext/dom/TextIsWhitespaceInElementContent.php",
         "ext/dom/TextSplitText.php",
         "ext/dom/TokenListAdd.php",
         "ext/dom/TokenListContains.php",
@@ -4543,9 +4546,9 @@
         "test/bootstrap-aot/lib_opcode/main.php"
     ],
     "totals": {
-        "inventory_files": 4309,
+        "inventory_files": 4312,
         "excluded": 0,
-        "eligible": 4309,
+        "eligible": 4312,
         "aot_lint_targets": 113,
         "aot_link_targets": 100,
         "aot_link_lib_targets": 1
diff --git a/docs/bootstrap-selfhost.md b/docs/bootstrap-selfhost.md
index 607f90a2d..dec287aed 100644
--- a/docs/bootstrap-selfhost.md
+++ b/docs/bootstrap-selfhost.md
@@ -2,7 +2,7 @@
 
 **Gen-0 without Zend:** `BOOTSTRAP_M5_NO_ZEND=1 make bootstrap-selfhost-link` installs `prelinked/bootstrap-gen0/bin-compile-aot` and links `compiler_minimal` without `php bin/compile.php` ([#3053](https://github.com/PurHur/php-compiler/issues/3053)). **M5 lib spine compile:** `BOOTSTRAP_NO_ZEND_FALLBACK=1 make bootstrap-selfhost-lib-spine-smoke` (default in link script) refuses host `php bin/compile.php` on the spine emit path ([#8716](https://github.com/PurHur/php-compiler/issues/8716)). **Contributor workflow:** [bootstrap-dev-workflow.md](bootstrap-dev-workflow.md) (tiered gen-1+ path, spine checklist, CI).
 
-**Project north star:** The **compiler fully compiles itself** — native AOT from `lib/` (no `vendor/` at cold boot), then compiles PHP and rebuilds the next compiler revision without Zend. **M2 spine:** **4311** / **4311** Phase A inventory (`php script/bootstrap-spine-count.php`; `check-selfhost-spine-coverage-sync.php`). **M5 daily gate:** `make north-star5-verify-fast` (~1–2 min) ✅; **`--strict`** (~1h) pre-merge only. Committed `prelinked/bootstrap-gen0/` sidecars + vendor **3/3** cold boot. **Hot loop:** VM driver execute probe ~**20ms**; full spine relink only with `BOOTSTRAP_VM_DRIVER_EXECUTE_PROBE_FULL_LINK=1` ([#2201](https://github.com/PurHur/php-compiler/issues/2201)). **Living tracker:** [#1492](https://github.com/PurHur/php-compiler/issues/1492) (was [#1056](https://github.com/PurHur/php-compiler/issues/1056)) · **re-root doc:** [self-host-target.md](self-host-target.md) · **generation ladder:** [bootstrap-generations.md](bootstrap-generations.md) · **M5 fast path:** [bootstrap-m5-fast-path.md](bootstrap-m5-fast-path.md) · public status: [development-status § North star](https://purhur.github.io/php-compiler/development-status.html#north-star-self-host). Parent tracking: [#78](https://github.com/PurHur/php-compiler/issues/78) (roadmap), [#212](https://github.com/PurHur/php-compiler/issues/212) (closed umbrella).
+**Project north star:** The **compiler fully compiles itself** — native AOT from `lib/` (no `vendor/` at cold boot), then compiles PHP and rebuilds the next compiler revision without Zend. **M2 spine:** **4312** / **4312** Phase A inventory (`php script/bootstrap-spine-count.php`; `check-selfhost-spine-coverage-sync.php`). **M5 daily gate:** `make north-star5-verify-fast` (~1–2 min) ✅; **`--strict`** (~1h) pre-merge only. Committed `prelinked/bootstrap-gen0/` sidecars + vendor **3/3** cold boot. **Hot loop:** VM driver execute probe ~**20ms**; full spine relink only with `BOOTSTRAP_VM_DRIVER_EXECUTE_PROBE_FULL_LINK=1` ([#2201](https://github.com/PurHur/php-compiler/issues/2201)). **Living tracker:** [#1492](https://github.com/PurHur/php-compiler/issues/1492) (was [#1056](https://github.com/PurHur/php-compiler/issues/1056)) · **re-root doc:** [self-host-target.md](self-host-target.md) · **generation ladder:** [bootstrap-generations.md](bootstrap-generations.md) · **M5 fast path:** [bootstrap-m5-fast-path.md](bootstrap-m5-fast-path.md) · public status: [development-status § North star](https://purhur.github.io/php-compiler/development-status.html#north-star-self-host). Parent tracking: [#78](https://github.com/PurHur/php-compiler/issues/78) (roadmap), [#212](https://github.com/PurHur/php-compiler/issues/212) (closed umbrella).
 
 ## Current gates
 
diff --git a/docs/pages/development-status.md b/docs/pages/development-status.md
index 78559ab9a..5801365de 100644
--- a/docs/pages/development-status.md
+++ b/docs/pages/development-status.md
@@ -15,7 +15,7 @@ permalink: /development-status.html
 | **North star** | Compiler compiles itself without Zend ([#1492](https://github.com/PurHur/php-compiler/issues/1492)) |
 | **v1.1.0 theme** | M5 fast-path stability; enum/property hooks; `preg_match` JIT; `spl_autoload*`; php-in-PHP JIT helpers ([#78](https://github.com/PurHur/php-compiler/issues/78)) |
 | **Wave 3** | Language **12/12** · Stdlib **13/13** on master ([#1380](https://github.com/PurHur/php-compiler/issues/1380)) |
-| **Spine SSOT** | `php script/bootstrap-spine-count.php` → **4311** / **4311** |
+| **Spine SSOT** | `php script/bootstrap-spine-count.php` → **4312** / **4312** |
 | **Builtin matrix** | **852** functions ([`docs/capabilities.md`](https://github.com/PurHur/php-compiler/blob/master/docs/capabilities.md)) |
 | **Try it** | [`docs/GETTING-STARTED.md`](https://github.com/PurHur/php-compiler/blob/master/docs/GETTING-STARTED.md) |
 
@@ -50,7 +50,7 @@ permalink: /development-status.html
 ### Still open (high signal)
 
 - **MCJIT execute** — `bin/jit.php -r` SIGSEGV ([#98](https://github.com/PurHur/php-compiler/issues/98))
-- **Literal spine ratio** — **4311/4311** ✅ (Jul 2026)
+- **Literal spine ratio** — **4312/4312** ✅ (Jul 2026)
 - **Compile-spine stub retirement** — shrink `PHP_COMPILER_SELFHOST_AOT` on M3 allowlist ([#1402](https://github.com/PurHur/php-compiler/issues/1402))
 - **007-ThrowsWeb AOT execute** — invalid POST segfault at runtime (link OK; slice `EXAMPLES_AOT_SMOKE_ONLY=007`)
 - **LLVM 14+ upgrade** — experimental `script/install-llvm14.sh` ([#174](https://github.com/PurHur/php-compiler/issues/174))
@@ -62,7 +62,7 @@ permalink: /development-status.html
 - **`phpc` CLI** — `run`, `serve`, `build`, `deploy`, `lint`, `test`, `init`, `doctor`
 - **Examples 000–009** — VM and AOT link/execute for the curated web subset
 - **Self-host M0** — `compiler_minimal bundle OK` ✅
-- **Self-host M2** — spine **4311/4311** ✅; native link + lint ✅
+- **Self-host M2** — spine **4312/4312** ✅; native link + lint ✅
 - **Self-host M3** — HelloWorld strict `emit_path=native` ✅ ([#1493](https://github.com/PurHur/php-compiler/issues/1493)); inventory argv `bin/compile.php` ✅ ([#3024](https://github.com/PurHur/php-compiler/issues/3024) closed); compile-smoke strict native ✅ ([#1937](https://github.com/PurHur/php-compiler/issues/1937))
 - **Self-host M4** — `make bootstrap-loop-probe` full ladder ✅; gen-2→gen-3 full-spine recompile ✅
 - **Self-host M5** — vendor prelink **3/3** ✅; **`make north-star5-verify-fast`** daily ✅; `--strict` pre-merge; gen-0 refreshed; VM probe ~**20ms**
@@ -92,7 +92,7 @@ See [`docs/bootstrap-selfhost.md`](https://github.com/PurHur/php-compiler/blob/m
 |-----------|--------|
 | **M0** — Small `lib/` bundle runs | ✅ |
 | **M1** — Compiler-shaped bundle + compile-smoke | ✅ |
-| **M2** — Spine toward full inventory | ✅ **4311** / **4311** |
+| **M2** — Spine toward full inventory | ✅ **4312** / **4312** |
 | **M3** — Native compiles PHP (no Zend emit) | ✅ Smoke + inventory argv driver strict native |
 | **M4** — Bootstrap loop (next revision) | ✅ `bootstrap-loop-probe` full ladder |
 | **M5** — Full self-host, no `vendor/` cold boot | ✅ Presenter strict + compiled-only empty `build/` cold boot ([#3053](https://github.com/PurHur/php-compiler/issues/3053)) |
diff --git a/docs/roadmap-wave3.md b/docs/roadmap-wave3.md
index 6fd093b25..97e7a2bdb 100644
--- a/docs/roadmap-wave3.md
+++ b/docs/roadmap-wave3.md
@@ -19,7 +19,7 @@ Regenerate capability truth: `php script/capability-matrix.php`, `php script/cap
 
 Related merges outside this wave: `goto` ([#1228](https://github.com/PurHur/php-compiler/issues/1228) / [#1333](https://github.com/PurHur/php-compiler/pull/1333)), anonymous classes ([#1233](https://github.com/PurHur/php-compiler/issues/1233) / [#1386](https://github.com/PurHur/php-compiler/pull/1386)).
 
-**M2 spine:** **4311** / **4311** (`php script/bootstrap-spine-count.php`) — full Phase A inventory in `compiler_lib_spine_smoke`; coverage sync ✅ (`check-selfhost-spine-coverage-sync.php`). Native spine **link** + **lint** ✅ ([#2134](https://github.com/PurHur/php-compiler/issues/2134), [#8559](https://github.com/PurHur/php-compiler/issues/8559)). **M5 daily gate:** `make north-star5-verify-fast` + VM probe ~20ms ([#2201](https://github.com/PurHur/php-compiler/issues/2201)); `--strict` pre-merge only. M4 gen-2→gen-3 recompile ✅. Target doc: [self-host-target.md](self-host-target.md)
+**M2 spine:** **4312** / **4312** (`php script/bootstrap-spine-count.php`) — full Phase A inventory in `compiler_lib_spine_smoke`; coverage sync ✅ (`check-selfhost-spine-coverage-sync.php`). Native spine **link** + **lint** ✅ ([#2134](https://github.com/PurHur/php-compiler/issues/2134), [#8559](https://github.com/PurHur/php-compiler/issues/8559)). **M5 daily gate:** `make north-star5-verify-fast` + VM probe ~20ms ([#2201](https://github.com/PurHur/php-compiler/issues/2201)); `--strict` pre-merge only. M4 gen-2→gen-3 recompile ✅. Target doc: [self-host-target.md](self-host-target.md)
 
 ## Language (#1354–#1366)
 
diff --git a/docs/self-host-target.md b/docs/self-host-target.md
index b9bc19c04..85aa059df 100644
--- a/docs/self-host-target.md
+++ b/docs/self-host-target.md
@@ -79,7 +79,7 @@ That is **M5**. Everything below is the honest path from today’s bootstrap to
 
 | Indicator | Formula | Jun 2026 |
 |-----------|---------|----------|
-| **M2 spine progress** | `require_once` units in `compiler_lib_spine_smoke` ÷ Phase A inventory file count | **4311** / **4311** (`php script/bootstrap-spine-count.php`) |
+| **M2 spine progress** | `require_once` units in `compiler_lib_spine_smoke` ÷ Phase A inventory file count | **4312** / **4312** (`php script/bootstrap-spine-count.php`) |
 | **Public “Self-host” row** | Same M2 ratio until M3–M5 gates add weight ([`development-status.md`](pages/development-status.md)) | **~97%** |
 | **M5 vendor prelink** | `object_ok` packages ÷ 3 | **3 / 3** (cfg, types, llvm) |
 | **Composite (internal)** | Milestone weights in table above (M0–M1 = 100%, M2 = spine %, M3–M5 = gate %) | **~90%** |
diff --git a/ext/brotli/BrotliExtensionPolicy.php b/ext/brotli/BrotliExtensionPolicy.php
new file mode 100644
index 000000000..e7b45d1c8
--- /dev/null
+++ b/ext/brotli/BrotliExtensionPolicy.php
@@ -0,0 +1,21 @@
+<?php
+
+declare(strict_types=1);
+
+namespace PHPCompiler\ext\brotli;
+
+use PHPCompiler\CompilerVersion;
+
+/**
+ * ext/brotli surface advertisement — php-src ext/brotli/brotli.c module registration (#17563).
+ *
+ * Pure PHP {@see VmBrotliNative} stays compiled in-tree but is withheld from extension_loaded()
+ * and function_exists() on the reference profile until {@see CompilerVersion::supportsBrotli()}.
+ */
+final class BrotliExtensionPolicy
+{
+    public static function advertisesExtension(): bool
+    {
+        return CompilerVersion::supportsBrotli() && VmBrotliNative::available();
+    }
+}
diff --git a/ext/brotli/Module.php b/ext/brotli/Module.php
index 49dbb8aaf..6be989e27 100644
--- a/ext/brotli/Module.php
+++ b/ext/brotli/Module.php
@@ -7,13 +7,16 @@
 use PHPCompiler\ModuleAbstract;
 
 /**
- * brotli extension module (kjdev/php-ext-brotli; issue #6814).
+ * brotli extension module (kjdev/php-ext-brotli; issue #6814, #17563).
+ *
+ * Register brotli_compress()/brotli_uncompress() when
+ * {@see BrotliExtensionPolicy::advertisesExtension()} — withheld on reference profile.
  */
 class Module extends ModuleAbstract
 {
     public function getFunctions(): array
     {
-        if (!VmBrotliNative::available()) {
+        if (!BrotliExtensionPolicy::advertisesExtension()) {
             return [];
         }
 
diff --git a/ext/standard/BuiltinIntrospectionPolicy.php b/ext/standard/BuiltinIntrospectionPolicy.php
index d778e0cfb..a885502ce 100644
--- a/ext/standard/BuiltinIntrospectionPolicy.php
+++ b/ext/standard/BuiltinIntrospectionPolicy.php
@@ -152,6 +152,9 @@ public static function extensionIsAdvertised(string $extension): bool
         if ('sqlite3' === $ext) {
             return \PHPCompiler\ext\sqlite3\Sqlite3ExtensionPolicy::advertisesExtension();
         }
+        if ('brotli' === $ext) {
+            return \PHPCompiler\ext\brotli\BrotliExtensionPolicy::advertisesExtension();
+        }
 
         return true;
     }
diff --git a/lib/CompilerVersion.php b/lib/CompilerVersion.php
index 5c5ed3ef9..2cc46e0ed 100644
--- a/lib/CompilerVersion.php
+++ b/lib/CompilerVersion.php
@@ -2007,6 +2007,17 @@ public static function supportsBz2(): bool
         return version_compare(self::languageProfileVersion(), '8.4.0', '>=');
     }
 
+    /**
+     * ext/brotli via pure PHP {@see \PHPCompiler\ext\brotli\VmBrotliNative} — withheld on reference profile (#17563).
+     *
+     * Gated on stable 8.4.0 / {@see languageProfileVersion()} so 8.4.0-dev reference profile matches Zend 8.2
+     * phantom gate (host ext-brotli absent). Enable forward profile via `PHP_COMPILER_PROFILE=8.4`.
+     */
+    public static function supportsBrotli(): bool
+    {
+        return version_compare(self::languageProfileVersion(), '8.4.0', '>=');
+    }
+
     /**
      * ext/sqlite3 exception surface — withheld on reference profile (#17106, #17194).
      *
diff --git a/test/compliance/JITTest.php b/test/compliance/JITTest.php
index 94d6f99c5..9711144f7 100755
--- a/test/compliance/JITTest.php
+++ b/test/compliance/JITTest.php
@@ -571,6 +571,15 @@ public static function providePHPTests(): \Generator
                 && str_contains($name, 'bz2_phantom')) {
                 continue;
             }
+            if (!CompilerVersion::supportsBrotli()
+                && (str_contains($name, 'brotli') || str_contains($name, 'brotli_'))
+                && !str_contains($name, 'brotli_phantom')) {
+                continue;
+            }
+            if (CompilerVersion::supportsBrotli()
+                && str_contains($name, 'brotli_phantom')) {
+                continue;
+            }
             if (!CompilerVersion::supportsBcmath()
                 && (str_contains($name, 'bcadd')
                     || str_contains($name, 'bcsub')
diff --git a/test/compliance/VMTest.php b/test/compliance/VMTest.php
index 58ecc138b..f443ef801 100755
--- a/test/compliance/VMTest.php
+++ b/test/compliance/VMTest.php
@@ -467,6 +467,15 @@ public static function providePHPTests(): \Generator
                 && str_contains($name, 'bz2_phantom')) {
                 continue;
             }
+            if (!CompilerVersion::supportsBrotli()
+                && (str_contains($name, 'brotli') || str_contains($name, 'brotli_'))
+                && !str_contains($name, 'brotli_phantom')) {
+                continue;
+            }
+            if (CompilerVersion::supportsBrotli()
+                && str_contains($name, 'brotli_phantom')) {
+                continue;
+            }
             if (!CompilerVersion::supportsBcmath()
                 && (str_contains($name, 'bcadd')
                     || str_contains($name, 'bcsub')
diff --git a/test/compliance/cases/stdlib/brotli_phantom.phpt b/test/compliance/cases/stdlib/brotli_phantom.phpt
new file mode 100644
index 000000000..14ba75fae
--- /dev/null
+++ b/test/compliance/cases/stdlib/brotli_phantom.phpt
@@ -0,0 +1,14 @@
+--TEST--
+stdlib brotli — not advertised on reference profile (#17563, ext/brotli)
+--FILE--
+<?php
+declare(strict_types=1);
+
+echo extension_loaded('brotli') ? "fail ext\n" : "ok ext\n";
+foreach (['brotli_compress', 'brotli_uncompress'] as $fn) {
+    echo function_exists($fn) ? "fail {$fn}\n" : "ok {$fn}\n";
+}
+--EXPECT--
+ok ext
+ok brotli_compress
+ok brotli_uncompress
diff --git a/test/compliance/cases/stdlib/brotli_roundtrip.phpt b/test/compliance/cases/stdlib/brotli_roundtrip.phpt
index 8c4490ec6..0396dc840 100644
--- a/test/compliance/cases/stdlib/brotli_roundtrip.phpt
+++ b/test/compliance/cases/stdlib/brotli_roundtrip.phpt
@@ -1,5 +1,10 @@
 --TEST--
 stdlib brotli_compress/brotli_uncompress round-trip via libbrotli FFI (#6814, kjdev/php-ext-brotli)
+--SKIPIF--
+<?php
+if (!\PHPCompiler\CompilerVersion::supportsBrotli()) {
+    die('skip brotli withheld on reference profile (#17563)');
+}
 --FILE--
 <?php
 $plain = 'hello brotli';
diff --git a/test/repro/maintainer_gap_brotli_phantom_extension.php b/test/repro/maintainer_gap_brotli_phantom_extension.php
new file mode 100644
index 000000000..380341280
--- /dev/null
+++ b/test/repro/maintainer_gap_brotli_phantom_extension.php
@@ -0,0 +1,16 @@
+<?php
+
+declare(strict_types=1);
+
+if (extension_loaded('brotli')) {
+    fwrite(STDERR, "FAIL: extension_loaded('brotli') true on reference profile\n");
+    exit(1);
+}
+foreach (['brotli_compress', 'brotli_uncompress'] as $fn) {
+    if (function_exists($fn)) {
+        fwrite(STDERR, "FAIL: function_exists('{$fn}') true on reference profile\n");
+        exit(1);
+    }
+}
+
+echo "ok\n";
diff --git a/test/selfhost/compiler_lib_spine_smoke/main.php b/test/selfhost/compiler_lib_spine_smoke/main.php
index f6b79cb28..6c854fe8f 100644
--- a/test/selfhost/compiler_lib_spine_smoke/main.php
+++ b/test/selfhost/compiler_lib_spine_smoke/main.php
@@ -66,6 +66,7 @@
 require_once __DIR__.'/../../../ext/bcmath/bcscale.php';
 require_once __DIR__.'/../../../ext/bcmath/bcsqrt.php';
 require_once __DIR__.'/../../../ext/bcmath/bcsub.php';
+require_once __DIR__.'/../../../ext/brotli/BrotliExtensionPolicy.php';
 require_once __DIR__.'/../../../ext/brotli/BrotliJitHelper.php';
 require_once __DIR__.'/../../../ext/brotli/JitBrotli.php';
 require_once __DIR__.'/../../../ext/brotli/Module.php';
diff --git a/test/unit/BrotliExtensionPolicyTest.php b/test/unit/BrotliExtensionPolicyTest.php
new file mode 100644
index 000000000..7bbae86ef
--- /dev/null
+++ b/test/unit/BrotliExtensionPolicyTest.php
@@ -0,0 +1,35 @@
+<?php
+
+declare(strict_types=1);
+
+namespace PHPCompiler;
+
+use PHPCompiler\CompilerVersion;
+use PHPCompiler\ext\brotli\BrotliExtensionPolicy;
+use PHPUnit\Framework\TestCase;
+
+/** BrotliExtensionPolicy phantom withhold on reference profile (#17563). */
+final class BrotliExtensionPolicyTest extends TestCase
+{
+    public function testAdvertisesExtensionFalseOnReferenceProfile(): void
+    {
+        self::assertFalse(CompilerVersion::supportsBrotli());
+        self::assertFalse(BrotliExtensionPolicy::advertisesExtension());
+    }
+
+    public function testAdvertisesExtensionTrueOnForwardProfileWhenCoreAvailable(): void
+    {
+        $prev = getenv('PHP_COMPILER_PROFILE');
+        putenv('PHP_COMPILER_PROFILE=8.4');
+        try {
+            self::assertTrue(CompilerVersion::supportsBrotli());
+            self::assertTrue(BrotliExtensionPolicy::advertisesExtension());
+        } finally {
+            if (false === $prev) {
+                putenv('PHP_COMPILER_PROFILE');
+            } else {
+                putenv('PHP_COMPILER_PROFILE='.$prev);
+            }
+        }
+    }
+}
diff --git a/test/unit/CompilerVersionGateTest.php b/test/unit/CompilerVersionGateTest.php
index ce2537203..ce140bf7f 100644
--- a/test/unit/CompilerVersionGateTest.php
+++ b/test/unit/CompilerVersionGateTest.php
@@ -269,6 +269,26 @@ public function testSupportsBz2TrueOnForwardProfile(): void
         }
     }
 
+    public function testSupportsBrotliFalseOnReferenceProfile(): void
+    {
+        $this->assertFalse(CompilerVersion::supportsBrotli());
+    }
+
+    public function testSupportsBrotliTrueOnForwardProfile(): void
+    {
+        $prev = getenv('PHP_COMPILER_PROFILE');
+        putenv('PHP_COMPILER_PROFILE=8.4');
+        try {
+            $this->assertTrue(CompilerVersion::supportsBrotli());
+        } finally {
+            if (false === $prev) {
+                putenv('PHP_COMPILER_PROFILE');
+            } else {
+                putenv('PHP_COMPILER_PROFILE='.$prev);
+            }
+        }
+    }
+
     public function testSupportsNextafterFalseOnReferenceProfile(): void
     {
         $this->assertFalse(CompilerVersion::supportsNextafter());