Breaking changes are not the only consideration, there is also trust. People may have vetted gruvbox and put their trust in its author. Silently changing who is in control of the gruvbox package may be problematic, especially if its a relatively recent fork (not big community support / review yet) and its not entirely clear who is behind it.

I'm not sure if it is easily possible with the current non-namespaced vim plugin infrastructure, but I'd prefer this to be added as a separate plugin (gruvbox-community or something).

Great comment! Since I don't think you can rename plugins in vim-plugin-names, I've added it in overrides.nix for now, I'll see if there is a better way to do this in the meantime ^^

I don't see any reason to hold this back for now, but keep in mind that the plugin won't be included in automatic updates. If you find the time, it'd be nice to add renaming ability to update.py (having lines such as gruvbox-community/community as gruvbox-community in vim-plugin-names).

Thanks for the contribution :)