Update on what happened in WebKit in the week from May 12 to May 19.
This week focused on infrastructure improvements, new releases that include security fixes, and featured external projects that use the GTK and WPE ports.
Cross-Port 🐱
Multimedia 🎥
GStreamer-based multimedia support for WebKit, including (but not limited to) playback, capture, WebAudio, WebCodecs, and WebRTC.
Fixed
a reference cycle in the mediastreamsrc element, which prevented its disposal.
JavaScriptCore 🐟
The built-in JavaScript/ECMAScript engine for WebKit, also known as JSC or SquirrelFish.
Added an internal class that will be
used to represent Temporal Duration objects in a way that allows for more
precise calculations. This is not a user-visible change, but will enable future
PRs to advance Temporal support in JSC towards completion.
WPE WebKit 📟
WPE Platform API 🧩
New, modern platform API that supersedes usage of libwpe and WPE backends.
Added an initial demo application to the GTK4 WPEPlatform implementation.
Releases 📦️
WebKitGTK
2.48.2 and
WPE WebKit 2.48.2 have
been released. These are paired with a security advisory (WSA-2025-0004:
GTK,
WPE), and therefore it is
advised to update.
On top of security fixes, these release also include correctness fixes, and support for CSS Overscroll Behaviour is now enabled by default.
Community & Events 🤝
GNOME Web has gained a preferences page that allows toggling WebKit features at run-time. Tech Preview builds of the browser will show the settings page by default, while in regular releases it is hidden and may be enabled with the following command:
gsettings set org.gnome.Epiphany.ui webkit-features-page true
This should allow frontend developers to test upcoming features more easily. Note that the settings for WebKit features are not persistent, and they will be reset to their default state on every launch.
Infrastructure 🏗️
Landed an improvement to error
reporting in the script within WebKit that runs test262 JavaScript tests.
The WebKit Test Runner (WKTR) will no longer crash if invalid UTF-8 sequences are written to the standard error stream, (e.g. from 3rd party libraries' debugging options.
Experimentation is ongoing to un-inline String::find(), which saves ~50 KiB
in the resulting binary size worth of repeated implementations of SIMD “find
character in UTF-16” and “find character in UTF-32” algorithms. Notably, the
algorithm for “find character in ASCII string” was not even part of the
inlining.
Added the LLVM
repository to the
WebKit container SDK. Now it is possible to easily install Clang 20.x with
wkdev-setup-default-clang --version=20.
Figured out that a performance bug related to jump threading optimization in Clang 18 resulted in a bottleneck adding up to five minutes of build time in the container SDK. This may be fixed by updating to Clang 20.x.
That’s all for this week!
