Very detailed explanations. I learned a bunch about the syntax highlighting and code understanding in Helix & friends just from reading this.

All the tree-sitter features and datastructures seem ideal for a query language to be bolted on - something that generalises beyond symbol search or “find all references” - guess since there’s an API this is a DSL for writing queries about your code.

Does something like this exist?

zed uses tree-sitter and has a powerful query engine (dsl is lisp scheme): https://zed.dev/blog/syntax-aware-editing#tree-queries