Those fun little processes tend to leak when debugging the extension (only debugging! It does not happen otherwise!) if you use the DevTools for the embedded webview. I reported the bug, but I don't know when it'll get fixed.
In the meantime, we can use this lovely gist
to constantly look for orphaned jcef_helper.exe processes and kill them.
If we don't, well, there will be pain.
The easiest way to run the script is uv run --script <url-to-the-raw-script>,
or downloading it and running the same locally.