diff --git a/.gitignore b/.gitignore
index a44a176..c8373ad 100644
--- a/.gitignore
+++ b/.gitignore
@@ -26,7 +26,6 @@ apps/mobile/android/
 apps/mobile/ios/
 
 # Bundled at build time (fetched, GPL — not vendored)
-apps/desktop/extensions/ublock-origin/
 
 # Ubuntu Touch click staging (assembled from the release tarball)
 distribution/ubuntu-touch/install/
diff --git a/apps/desktop/launcher/tronbrowser b/apps/desktop/launcher/tronbrowser
index 58f248b..60da645 100755
--- a/apps/desktop/launcher/tronbrowser
+++ b/apps/desktop/launcher/tronbrowser
@@ -18,7 +18,7 @@ while [ -L "$SELF" ]; do
   esac
 done
 DIR="$(CDPATH= cd -- "$(dirname -- "$SELF")" && pwd)"
-EXTBASE_SRC="$DIR/extensions"   # holds ai-sidebar + ublock-origin (uBlock Origin)
+EXTBASE_SRC="$DIR/extensions"   # holds ai-sidebar + marksyncr
 
 # --- Tor mode -------------------------------------------------------------
 # `tron --tor [url...]` routes traffic through a local Tor daemon (SOCKS5) and
@@ -441,8 +441,10 @@ if [ "$TOR" != "1" ]; then
   printf '%s\n' "$ENGINE" > "$ENGINE_MARK" 2>/dev/null || true
 fi
 
-# Keep Manifest V2 working so uBlock Origin (MV2) loads — recent Chromium disables
-# MV2 by default. (Ungoogled keeps MV2, but force it off everywhere to be safe.)
+# Keep Manifest V2 working — recent Chromium disables MV2 by default, which
+# silently breaks any MV2 extension the user installed themselves. We no longer
+# bundle one, but the kill switch is not ours to flip on their behalf.
+# (Ungoogled keeps MV2, but force it off everywhere to be safe.)
 MV2_KEEP="ExtensionManifestV2Disabled,ExtensionManifestV2Unsupported,ExtensionManifestV2DeprecationWarning,ExtensionManifestV2DeprecationUnsupported"
 FLAGS="--user-data-dir=$DATA --class=TronBrowser --no-first-run --no-default-browser-check --no-pings --disable-background-networking --disable-breakpad --disable-domain-reliability --disable-sync --disable-features=Translate,OptimizationHints,InterestFeedContentSuggestions,$MV2_KEEP --load-extension=$EXT"
 
@@ -480,8 +482,8 @@ fi
 #
 # --enable-features / --disable-features merge rather than being replaced: they
 # are comma-separated lists, and dropping ours wholesale would quietly re-enable
-# the Manifest V2 kill switch (uBlock Origin stops loading) just because the
-# caller wanted one unrelated feature. Rotating through "$@" to pull those two
+# the Manifest V2 kill switch (every MV2 extension stops loading) just because
+# the caller wanted one unrelated feature. Rotating through "$@" to pull those two
 # out is the same idiom --tor is stripped with above.
 #
 # This runs BEFORE the Tor block on purpose. Tor's proxy flags are a guarantee,
diff --git a/apps/desktop/launcher/tronbrowser.cmd b/apps/desktop/launcher/tronbrowser.cmd
index 36d19e0..c1aa39a 100644
--- a/apps/desktop/launcher/tronbrowser.cmd
+++ b/apps/desktop/launcher/tronbrowser.cmd
@@ -2,7 +2,7 @@
 setlocal enabledelayedexpansion
 rem TronBrowser launcher (Windows). Runs Ungoogled Chromium ONLY (never Chrome,
 rem Edge, Brave, or regular Chromium) with TronBrowser privacy flags + bundled
-rem extensions (AI sidebar + uBlock Origin). `tron <url>` passes URLs through.
+rem extensions (AI sidebar + MarkSyncr). `tron <url>` passes URLs through.
 rem Mirrors apps/desktop/launcher/tronbrowser (POSIX). Override the binary with
 rem set "TRONBROWSER_BROWSER=C:\path\to\ungoogled-chromium\chrome.exe".
 set "DIR=%~dp0"
diff --git a/apps/desktop/scripts/build-release.sh b/apps/desktop/scripts/build-release.sh
index 9a79f6d..f8c0f8f 100755
--- a/apps/desktop/scripts/build-release.sh
+++ b/apps/desktop/scripts/build-release.sh
@@ -1,6 +1,6 @@
 #!/usr/bin/env bash
-# Assemble TronBrowser release archives (launcher shim + AI sidebar + uBlock
-# Origin + chromium-web-store extensions)
+# Assemble TronBrowser release archives (launcher shim + AI sidebar + MarkSyncr
+# + chromium-web-store extensions)
 # for a given platform. Until the native fork binary is built, this packages the
 # launcher; asset names are stable so install.sh / package managers are unchanged.
 #
@@ -14,25 +14,6 @@ DESKTOP="$REPO_ROOT/apps/desktop"
 OUT="$REPO_ROOT/dist"
 mkdir -p "$OUT"
 
-# Fetch uBlock Origin ONCE (the per-platform stage() copies from here). Full
-# uBlock Origin is MV2 — Ungoogled Chromium keeps MV2 support, so we ship the
-# real thing (not uBO Lite). The release asset name carries the version, so we
-# resolve the latest .chromium.zip via the GitHub API. Entirely non-fatal.
-UBO_SRC=""
-fetch_ublock() {
-  command -v python3 >/dev/null 2>&1 || { echo "  ! uBlock skipped (no python3)"; return; }
-  local url
-  url="$(curl -fsSL https://api.github.com/repos/gorhill/uBlock/releases/latest 2>/dev/null \
-    | python3 -c 'import sys,json;d=json.load(sys.stdin);print(next((a["browser_download_url"] for a in d["assets"] if a["name"].endswith(".chromium.zip")),""))' 2>/dev/null)" || true
-  [ -n "$url" ] || { echo "  ! uBlock resolve skipped (non-fatal)"; return; }
-  local z d m; z="$(mktemp)"; d="$(mktemp -d)"
-  if curl -fsSL "$url" -o "$z" 2>/dev/null && unzip -q -o "$z" -d "$d" 2>/dev/null; then
-    m="$(find "$d" -maxdepth 2 -name manifest.json | head -1)"
-    if [ -n "$m" ]; then UBO_SRC="$(dirname "$m")"; echo "  + fetched uBlock Origin ($url)"; fi
-  fi
-  rm -f "$z"  # keep $d (UBO_SRC lives inside) until the script exits
-}
-
 # Fetch MarkSyncr ONCE from the Chrome Web Store (latest published CRX). Open
 # source (github.com/profullstack/marksyncr.com), MV3 bookmark sync. Non-fatal.
 MKS_ID="hjcjjcpialiakkalcgadnfnoomdaegjg"
@@ -141,11 +122,6 @@ DESKTOP
   # installs are instead handled by the AI sidebar's install-helper.js content
   # script (adds a working "Add to TronBrowser" button → CRX install prompt).
 
-  # Default ad/tracker blocker: uBlock Origin (fetched once into $UBO_SRC).
-  if [ -n "$UBO_SRC" ] && [ -d "$UBO_SRC" ]; then
-    mkdir -p "$s/extensions/ublock-origin"
-    cp -R "$UBO_SRC/." "$s/extensions/ublock-origin/"
-  fi
   # Bundled bookmark sync: MarkSyncr (fetched once into $MKS_SRC).
   if [ -n "$MKS_SRC" ] && [ -d "$MKS_SRC" ]; then
     mkdir -p "$s/extensions/marksyncr"
@@ -164,7 +140,6 @@ build_archive() { # ext-type
   rm -rf "$t"
 }
 
-fetch_ublock
 fetch_marksyncr
 
 case "$PLATFORM" in
diff --git a/apps/desktop/test/launcher.test.ts b/apps/desktop/test/launcher.test.ts
index d4a3946..4b1074e 100644
--- a/apps/desktop/test/launcher.test.ts
+++ b/apps/desktop/test/launcher.test.ts
@@ -100,7 +100,7 @@ describe('launcher flags', () => {
   });
 
   it('merges --disable-features, keeping the Manifest V2 kill switch off', () => {
-    // Dropping ours here would stop uBlock Origin (MV2) from loading.
+    // Dropping ours here would stop every MV2 extension from loading.
     const { argv } = run(['--disable-features=Foo']);
     const disabled = valueOf(argv, '--disable-features');
     expect(disabled).toHaveLength(1);
diff --git a/eslint.config.js b/eslint.config.js
index 7aa5bcf..bf2cdd1 100644
--- a/eslint.config.js
+++ b/eslint.config.js
@@ -16,7 +16,6 @@ export default tseslint.config(
       '**/.expo/**',
       '**/node_modules/**',
       'apps/desktop/chromium/**',
-      'apps/desktop/extensions/ublock-origin/**', // fetched at build time, GPL, not vendored
       'pnpm-lock.yaml',
     ],
   },