Source? All I see is that Valve kindly asked him to take down the project before Nintendo comes after them for using Nintendo's proprietary libraries, but the project could hypothetically continue if he switched to an open source library instead.
Is it? That's not listed as an option here alongside Endravour, Fedora, etc. https://docs.buddiesofbudgie.org/user/getting-budgie/
Any extension that you cannot install directly from Codium, you can just manually download/install the VSIX file for from GitHub or whatever. https://github.com/VSCodium/vscodium/blob/master/docs/index.md#extensions-marketplace
Firefox supports the standard just finehttps://developer.mozilla.org/en-US/docs/Web/Accessibility/Sarcasm/Attributes
I use Fedora btw