I am working on that https://github.com/gritzko/librdx Conflictless merge and overlay branches (ie freely attachable/detachable by a click). That was the pie-in-the-sky of the CRDT community for maybe 15 years. My current approach is RDX tree CRDT effectively mapping to the AST tree of the program. Like CRDT DOM for the AST, because line based diffs are too clumsy for that.

Back in the day, JetBrains tried revision-controlling AST trees or psi-nodes in their parlance. That project was cancelled, as it became a research challenge. That was 10 years ago or so. At this point, things may work out well, time will tell.