I'm watching it with attention but some stuff is concerning:

* Some binaries in the source tree like https://github.com/lem-project/lem/tree/main/extensions/term...

* Commit messages aren't really descriptive.

* PRs and issues lingering in the void.

* Working around the strange inferior process thing (cf https://github.com/lem-project/lem/issues/1076) that could be replaced by uiop:launch-program when a tty/pty isn't needed; still no LSP in c-mode, and forget C++, obviously.

Well, let's be honest, it's very interesting but still a one-man effort, as far as the core editor goes, so these are pretty normal.