It's possible to build #flatpak applications with #buildstream (for example, see Squey(?): https://gitlab.com/squey/squey/-/blob/main/buildstream/app.yml?ref_type=heads)

I think it'd be cool if someone worked on better UX for using buildstream as a Flatpak manifest format.

buildstream/app.yml · main · Squey / Squey · GitLab

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