ToDo: diffs FF134-FF135

[earthlng]

FF135 release date: Feb. 4th 2025

FF135 release notes
FF135 for developers
FF135 security advisories

---

71 diffs ( 41 new, 10 gone, 20 different )

new in v135.0:

pref("accessibility.typeaheadfind.wrappedSoundURL", "");
pref("app.update.multiSessionInstallLockout.enabled", true);
pref("app.update.multiSessionInstallLockout.timeoutMs", 345600000);
pref("apz.keyboard.focus-optimization", false);
pref("apz.mousemove_hittest_optimization.enabled", false);
pref("apz.popups_without_remote.enabled", false);
pref("browser.ml.chat.prompts.4", "{\"id\":\"proofread\", \"l10nId\":\"genai-prompts-proofread\"}");
pref("browser.newtabpage.activity-stream.discoverystream.sections.blocked", "");
pref("browser.newtabpage.activity-stream.discoverystream.sections.following", "");
pref("browser.newtabpage.activity-stream.discoverystream.sections.personalization.enabled", false);
pref("browser.newtabpage.activity-stream.newtabAdSize.billboard", false);
pref("browser.newtabpage.activity-stream.newtabAdSize.billboard.position", "3");
pref("browser.newtabpage.activity-stream.newtabAdSize.leaderboard", false);
pref("browser.newtabpage.activity-stream.newtabAdSize.leaderboard.position", "3");
pref("browser.profiles.sync.allow-danger-merge", false);
pref("browser.shopping.experience2023.shoppingSidebar", true);
pref("browser.tabs.dragdrop.moveOverThresholdPercent", 70);
pref("browser.translations.useLexicalShortlist", false);
pref("browser.urlbar.unifiedSearchButton.always", false);
pref("browser.urlbar.weather.uiTreatment", 0);
pref("captchadetection.actor.enabled", false);
pref("captchadetection.loglevel", "Warn");
pref("dom.event.mouse.fractional_coordinates.trusted.enabled", false);
pref("dom.event.mouse.fractional_coordinates.untrusted.enabled", false);
pref("dom.event.pointer.fractional_coordinates.enabled", true);
pref("identity.fxaccounts.toolbar.syncSetup.panelAccessed", false);
pref("layout.css.moz-user-input.enabled", false);
pref("media.ffvpx-hw.enabled", false);
pref("media.gmp.coder-shutdown-timeout-ms", 1000);
pref("media.webrtc.codec.video.av1.enabled", false);
pref("media.webrtc.codec.video.av1.experimental_preferred", false);
pref("network.cookie.sameSite.laxByDefaultWarningsForBeta", false);
pref("network.http.idempotencyKey.enabled", false);
pref("network.http.retry_with_another_half_open", false);
pref("network.socket.attach_mock_network_layer", false);
pref("nimbus.telemetry.targetingContextEnabled", true);
pref("permissions.manager.remote.enabled", false);
pref("security.mls.enabled", false);
pref("sidebar.revamp.round-content-area", false);
pref("signon.firefoxRelay.firstOfferVersionFallback", "control");
pref("widget.windows.pip-decorations.enabled", false);

removed, renamed or hidden in v135.0:

pref("browser.shopping.experience2023.ads.exposure", false);
pref("dom.block_multiple_popups", true);
pref("layout.forms.reveal-password-context-menu.enabled", true);
pref("network.dns.use_override_as_peer_address", false);
pref("network.http.throttle.read-interval-ms", 500);
pref("network.http.throttle.read-limit-bytes", 8000);
pref("network.http.throttle.version", 1);
pref("reader.colors_menu.enabled", true);
pref("reader.improved_text_menu.enabled", true);
pref("webextensions.storage.sync.enabled", true);

changed in v135.0:

pref("browser.contentblocking.report.vpn_regions", "as,at,au,bd,be,bg,br,ca,ch,cl,co,cy,cz,de,dk,ee,eg,es,fi,fr,gb,gg,gr,hr,hu,id,ie,im,in,io,it,je,ke,kr,lt,lu,lv,ma,mp,mt,mx,my,ng,nl,no,nz,pl,pr,pt,ro,sa,se,sg,si,sk,sn,th,tr,tw,ua,ug,uk,um,us,vg,vi,vn,za"); // prev: "ca,my,nz,sg,gb,gg,im,io,je,uk,vg,as,mp,pr,um,us,vi,de,fr,at,be,ch,es,it,ie,nl,se,fi,bg,cy,cz,dk,ee,hr,hu,lt,lu,lv,mt,pl,pt,ro,si,sk"
pref("browser.ml.defaultModelMemoryUsage", 1); // prev: 2
pref("browser.navigation.requireUserInteraction", true); // prev: false
pref("browser.newtabpage.activity-stream.support.url", "https://support.mozilla.org/1/firefox/135.0/WINNT/en-US/new-tab"); // prev: "https://support.mozilla.org/1/firefox/134.0/WINNT/en-US/new-tab"
pref("dom.events.mouse-pointer-boundary.keep-enter-targets-after-over-target-removed", true); // prev: false
pref("dom.forms.always_allow_key_and_focus_events.enabled", true); // prev: false
pref("dom.forms.fieldset_disable_only_descendants.enabled", true); // prev: false
pref("gfx.canvas.accelerated.cache-items", 8192); // prev: 2048
pref("gfx.font_rendering.cleartype_params.force_gdi_classic_for_families", ""); // prev: "Arial,Consolas,Courier New,Microsoft Sans Serif,Segoe UI,Tahoma,Trebuchet MS,Verdana"
pref("gfx.font_rendering.cleartype_params.force_gdi_classic_max_size", 0); // prev: 15
pref("javascript.options.experimental.json_parse_with_source", true); // prev: false
pref("javascript.options.wasm_call_ref_inlining_percent", 40); // prev: 50
pref("javascript.options.wasm_lazy_tiering_for_gc", true); // prev: false
pref("network.http.http3.enable_kyber", true); // prev: false
pref("places.history.floodingPrevention.enabled", true); // prev: false
pref("privacy.resistFingerprinting.target_video_res", 1080); // prev: 480
pref("remote.events.async.enabled", true); // prev: false
pref("security.pki.certificate_transparency.mode", 2); // prev: 0
pref("security.sandbox.content.level", 8); // prev: 7
pref("ui.panel.default_level_parent", true); // prev: false

---

ignore

click me for details

==NEW

==REMOVED, RENAMED or HIDDEN

==CHANGED

[earthlng]

some bugzilla tickets

• accessibility.typeaheadfind.wrappedSoundURL
  Bug 281533 - Add findbar WRAPPED sound,

• app.update.multiSessionInstallLockout.enabled
  Bug 1907127 - Add support for writing update.timestamp

• app.update.multiSessionInstallLockout.timeoutMs
  Bug 1907127 - Add support for writing update.timestamp

• apz.keyboard.focus-optimization
  Bug 1942969 - Do not schedule a paint for all focus changing events. a=RyanVM

• apz.mousemove_hittest_optimization.enabled
  Bug 1943415 - Put the APZ mouse-move hit test optimization behind a pref. a=RyanVM

• apz.popups_without_remote.enabled
  Bug 1938266 - Disable APZ in popup window without remote content behind a pref.

• browser.contentblocking.report.vpn_regions
  Bug 1930961 - Firefox VPN promo regions list is out of date

• browser.ml.chat.prompts.4
  Bug 1932930 Add "Writing & Grammar Check" option to list of AI Chatbot Prompts,

• browser.ml.defaultModelMemoryUsage
  Bug 1932054 - activate memory guardrail
  Bug 1885253 - make sure we don't ask for 2GiB in the CI by default

• browser.navigation.requireUserInteraction
  Bug 1939691 - Re-enable back-button intervention by default on all channels.
  Bug 1929534 - Restrict back-button intervention to only early-beta and nightly.
  Bug 1926290 - Enable the back-button intervention by default.

• browser.profiles.sync.allow-danger-merge
  Bug 1929705: Add new sync warning dialogs to support incoming profile switching

• browser.shopping.experience2023.ads.exposure
  Bug 1901615 - Remove ads exposure counter from telemetry metrics -

• browser.shopping.experience2023.shoppingSidebar
  Bug 1916547 - Part 1: Render Review Checker in the new sidebar.

• browser.tabs.dragdrop.moveOverThresholdPercent
  Bug 1933258 - Add pref for when to move other tabs out of the way during drag and drop.

• browser.translations.useLexicalShortlist
  Bug 1940972 - Introduce useLexicalShortlist pref a=RyanVM

• browser.urlbar.unifiedSearchButton.always
  Bug 1937363: Use Unified Search Button full name

• browser.urlbar.weather.uiTreatment
  Bug 1938517 - Implement new "simplest" weather suggestion UI.

• captchadetection.actor.enabled
  Bug 1941875: Disable captcha detection in non-nightly builds.

• captchadetection.loglevel
  Bug 1913421: Introduce Captcha Detection Actor.

• dom.block_multiple_popups
  Bug 1933321 - Get rid of dom.block_multiple_popups;

• dom.event.mouse.fractional_coordinates.trusted.enabled
  Bug 1680669 - part 6: Make methods of MouseEvent and static methods of Event aware of fractional coordinates

• dom.event.mouse.fractional_coordinates.untrusted.enabled
  Bug 1680669 - part 6: Make methods of MouseEvent and static methods of Event aware of fractional coordinates

• dom.event.pointer.fractional_coordinates.enabled
  Bug 1833963 - Ship fractional coordinates of PointerEvent
  Bug 1680669 - part 6: Make methods of MouseEvent and static methods of Event aware of fractional coordinates

• dom.events.mouse-pointer-boundary.keep-enter-targets-after-over-target-removed
  Bug 1938528 - Enable new mouse and pointer boundary event behavior in the release channel

• dom.forms.always_allow_key_and_focus_events.enabled
  Bug 1819938 - Enable dom.forms.always_allow_key_and_focus_events by default;

• dom.forms.fieldset_disable_only_descendants.enabled
  Bug 1819938 - Enable dom.forms.fieldset_disable_only_descendants.enabled by default;

• gfx.canvas.accelerated.cache-items
  Bug 1927053 - Optimize GlyphCache lookups.

• gfx.font_rendering.cleartype_params.force_gdi_classic_for_families
  Bug 1942335 - Stop forcing GDI Classic rendering for a list of common Windows fonts. a=RyanVM
  Bug 1920733 - For Nightly and early Beta, stop forcing GDI Classic rendering on certain core Windows fonts.

• gfx.font_rendering.cleartype_params.force_gdi_classic_max_size
  Bug 1942335 - Stop forcing GDI Classic rendering for a list of common Windows fonts. a=RyanVM
  Bug 1920733 - For Nightly and early Beta, stop forcing GDI Classic rendering on certain core Windows fonts.

• identity.fxaccounts.toolbar.syncSetup.panelAccessed
  Bug 1935503: Add indicator when sync is disabled for enrolled users

• javascript.options.experimental.json_parse_with_source
  Bug 1934622 - Default to enabling JSON.parse with source
  Bug 1925334 - Default to disabling JSON.parse with source

• javascript.options.wasm_call_ref_inlining_percent
  Bug 1929320 - wasm: allow inlining more than one call target with call_ref.
  Bug 1921216 - wasm speculative inlining: track multiple targets per call-ref callsite.

• javascript.options.wasm_lazy_tiering_for_gc
  Bug 1924559 - wasm: Enable lazy tiering for wasm GC modules.

• layout.css.moz-user-input.enabled
  Bug 1935198 - Add a pref to unship -moz-user-input from content.

• layout.forms.reveal-password-context-menu.enabled
  Bug 1936930 - Add reveal password for password field context menus in chrome.

• media.ffvpx-hw.enabled
  Bug 1936047 Disable ffvpx VP9 and AV1 hw decoding on Windows Nightly
  Bug 1932772 - part4 : use ffvpx linker on the gpu process in order to support hw decoding.

• media.gmp.coder-shutdown-timeout-ms
  Bug 1936275 - Avoid deadlock with GMP decoder/encoder shutdown.

• media.webrtc.codec.video.av1.enabled
  Bug 1921154 - add AV1 pref;r=pehrsons

• media.webrtc.codec.video.av1.experimental_preferred
  Bug 1921154 - add experimental pref to prefer AV1;r=dbaker

• network.cookie.sameSite.laxByDefaultWarningsForBeta
  Bug 1929358 - Remove warning messages for lax-by-default in non-nightly env,

• network.dns.use_override_as_peer_address
  Bug 1937522 - Remove network.dns.use_override_as_peer_address,
  Bug 1933672 - Test case,

• network.http.http3.enable_kyber
  Bug 1941041 - enable mlkem768x25519 in h3 in release. a=RyanVM
  Bug 1926127 - enable mlkem768x25519 in h3 for early beta desktop builds.

• network.http.idempotencyKey.enabled
  Bug 1830022 - add Idempotency-Key header to post request.

• network.http.retry_with_another_half_open
  Bug 1533273 - Add retry logic for half-open sockets when one fails and another is still connecting,

• network.http.throttle.read-interval-ms
  Bug 1870091 - Remove HTTP throttling v2 prefs.

• network.http.throttle.read-limit-bytes
  Bug 1870091 - Remove HTTP throttling v2 prefs.

• network.http.throttle.version
  Bug 1870091 - Remove HTTP throttling v2 (network.http.throttle.version 2).

• network.socket.attach_mock_network_layer
  Bug 1937522 - Introduce a mock network layer that supports overwriting NetAddr,

• nimbus.telemetry.targetingContextEnabled
  Bug 1936317 - Don't record targeting context metrics in artifact builds

• permissions.manager.remote.enabled
  Bug 1919558 - Part 6: Add RemotePermissionService to get default permissions from remote settings

• places.history.floodingPrevention.enabled
  Bug 1915404 - Enable history flooding prevention in Release.
  Bug 1891145: Implement history flooding protection

• privacy.resistFingerprinting.target_video_res
  Bug 1762919 - Make dropped frame statistics more realistic.

• reader.colors_menu.enabled
  Bug 1903156 - Remove duplicate code from older menus once the new menus land.
  Bug 1899366 - Flip prefs to enable new text and layout + theme menus by default.
  Bug 1876432 - Added support for custom themes as its own menu in Reader View.

• reader.improved_text_menu.enabled
  Bug 1903156 - Remove duplicate code from older menus once the new menus land.
  Bug 1899366 - Flip prefs to enable new text and layout + theme menus by default.
  Bug 1880658 - Added text alignment controls in Reader menu.

• remote.events.async.enabled
  Bug 1922077 - [remote] Enable processing and dispatching actions via the parent process by default.
  Bug 1904665 - [remote] Prepare the Remote Agent code base for parent process event dispatching.

• security.mls.enabled
  Bug 1883321 - Part 1: Messaging Layer Security module, prefs and FFI.

• security.pki.certificate_transparency.mode
  Bug 1927085 - enforce certificate transparency in release on desktop a=RyanVM
  Bug 1929459 - enforce certificate transparency in early beta
  Bug 1929459 - enforce certificate transparency in early beta a=dmeehan

• security.sandbox.content.level
  Bug 1936532: Disable USER_RESTRICTED by default for content process in Release for Fx134.
  Bug 1403931: Enable USER_RESTRICTED on content process sandbox for Release.
  Bug 1900175: Enable USER_RESTRICTED for content processes on Nightly.

• sidebar.revamp.round-content-area
  Bug 1934640 - Don't let the rounded content area ride the trains for now.

• signon.firefoxRelay.firstOfferVersionFallback
  Bug 1921484 - feat(firefoxRelay): add UX treatment experimentation

• ui.panel.default_level_parent
  Bug 1936194 - Fix backwards pref name ui.panel.default_level_parent.

• webextensions.storage.sync.enabled
  Bug 1888472 - Refactored webext-storage sync logic with uniffied component API
  Bug 1888472 - Refactored webext-storage sync logic with uniffied component API calls

• widget.windows.pip-decorations.enabled
  Bug 1934375 - Take over whole non-client area for PiP windows again, for now.