Thanks. I probably could have answered my own question had I simply looked here:

https://github.com/gpui-ce/gpui-ce/pulls

and here:

https://github.com/zed-industries/zed/pulls?q=is%3Apr+is%3Ao...

Sadly it doesn't actually look like gpui-ce has any activity, the maintainer merged one pull request (literally, #1) and then stopped. They should've just added more community maintainers to the GPUI repo directly rather than having a fork.