I think that there should be some sort of standardized, language-agnostic metadata format for semantically indexing a codebase. It could include e.g type information for expressions or declared variables (for languages that infer types), and an index of symbols and how they're connected.

This metadata file would be generated by a language-specific tool. For instance, Cargo could generate it for Rust projects, ctags/cmake for C / C++, Sorbet for Ruby.

Then a service like Github / Gitlab / your own homegrown code viewer could provide things like "Show type", "Jump to source" without ever needing to build a language-specific parser or interpreter (which seems arbitrarily difficult, most build systems provide escape hatches, so you can't assume much about project structure).

Basically, LSP as a static file in a standard format that tools can read to understand a codebase, without needing to model the language's semantics.