It sounds like you don’t want a dev container but a dev shell. Have a look at Nix flakes. This allows you to ship your dev environment as code but without the hassle of running inside a container. All your local tools will work and pickup whatever you configured in the flake.

As mentioned on Mastodon (https://mastodon.social/@dpom@fosstodon.org/113460954769241417) there seems to be no way to do it at the moment :(

The selling point of Ice (the underlying framework for libcosmic) is the cross-platform compatibility. Can I use libcosmic cross-plat as well, or is it more a specialisation of Ice for Linux with the clear focus on the Cosmic desktop? Would be cool to re-use some widget etc.

What is missing in the existing ones?

Never used bstr. What was interesting about it?

I like that idea! I'll try to share more, what I'm working on and where the difficulties are.