The git repo is here: https://github.com/scip-code/scip
Looks like it's defined using protocol buffers, with "rich Go and Rust bindings" and links to implementations for many other languages.
I have been using https://github.com/jacktasia/dumb-jump to quickly jump to definitions. LSP is hit or miss; in some languages, it works great, while in others, the implementation is not so good. I have been thinking about a middle ground based on Tree-sitter. GitHub uses Tree-sitter to power code navigation, but unfortunately, I can't find anything good that I can use offline. Why is there no ctags equivalent powered by Tree-sitter?
Something something powers go to definition… is this an implementation of an LSP server? Or a subset of what’s needed to implement LSP? A formerly proprietary alternative to LSP?
Structure and Computer of Interpretation Programs
Oh, not SICP.