TL;DR: the release artifacts created by the GH Actions seem good to me, and this PR looks ready to merge and the release accepted.

Details:

This is my first shot at supporting the Jupyter Desktop update/release process, so feedback welcome.

I've done a basic manual smoke test of the CICD artifacts on Windows 11 (Intel N100), macOS 15.6 (Apple silicon), and Ubuntu 24.04 LTS (WSL on Intel N100). This included installing the embedded environment, and confirming a basic Jupyter Notebook could be created and that version numbers matched between Desktop and the jupyterlab.__version__ value. From my very-new-to-this perspective all look good. Only a few things to note:

• Ubuntu version returned some terminal warning messages when starting, but then appeared to start properly (see output below).
• Mac version required jumping through some hoops due to software security restrictions which (falsely, I think) reported "Application is damaged and cannot be opened" -- this required an xattr -c /Applications/JupyterLab.app hack to get around
• I was surprised to see that the embedded environment on Linux installed into the ~/.config directory as this is meant for relatively small and user-configurable text config files, not for many GB of Python (and other) libraries.
• The Ubuntu icon for Jupyter Desktop was Tux. This may have been a side-effect of me using Ubuntu on WSL, but other GUI apps have the expected app icons.
• I saw no developer notes for how to test a new release, so I came up with my own basic smoke test as described above.
• The GH build Actions show 18 warnings none of which seem serious but should be addressed at some point (I didn't try to figure out if they are upstream, or the responsibility of Desktop to fix).

@krassowski or @mbektas what else needs to be done to accept the PR and merge it? Anything else required in the release process?

Ubuntu (on WSL running on an Intel N100) produced these messages immediately on startup. I don't know how to interpret if they are real problems or not. They say ERROR but Desktop started just fine and my smoke tests ran just fine.

$ jlab
[8144:0818/175744.260198:ERROR:viz_main_impl.cc(196)] Exiting GPU process due to errors during initialization
[8203:0818/175744.572606:ERROR:viz_main_impl.cc(196)] Exiting GPU process due to errors during initialization
[8219:0818/175744.989759:ERROR:viz_main_impl.cc(196)] Exiting GPU process due to errors during initialization
[8244:0818/175745.249027:ERROR:viz_main_impl.cc(196)] Exiting GPU process due to errors during initialization
[8260:0818/175745.379014:ERROR:viz_main_impl.cc(196)] Exiting GPU process due to errors during initialization
[8276:0818/175745.728982:ERROR:viz_main_impl.cc(196)] Exiting GPU process due to errors during initialization
[8186:0818/175745.904012:ERROR:command_buffer_proxy_impl.cc(127)] ContextResult::kTransientFailure: Failed to send GpuControl.CreateCommandBuffer.
[8194:0818/175745.906503:ERROR:command_buffer_proxy_impl.cc(127)] ContextResult::kTransientFailure: Failed to send GpuControl.CreateCommandBuffer.

@telamonian this gives an idea of the way I'm doing the release PR review.

Thank you for testing @ijstokes, I will merge this now!

I think some immediate action items would be:

• the jupyterlab update action is failing (https://github.com/jupyterlab/jupyterlab-desktop/actions/runs/17105910291), this is the latest PR which it generated but we are far into 4.4.x cycle
• we need to update electron to a supported version
• we should handle the sandboxing issues which prevent running on recent Ubuntu and MacOS smoothly