Dang, 45? I mean, I assume that's C++, Go, Python, Java, and JavaScript/TypeScript. And languages for build scripts, plus stuff like md and rst. And some shells. Probably embedded languages like lua, sql, graphql, and maybe some shading languages. Fortran and some assembly languages, a forth or two for low level bringup or firmware. Dart of course.
But all of those is still less than 30. What am I missing?
Three general categories missing:
1. The core stack of internal (or internally created but also external) - protobuf, gcl, etc
2. Some more well-known languages that aren't as big in Google, but are still used and people wrote indexers for: C#, lisp, Haskell, etc.
3. All the random domain specific langs that people built and then worte indexers for.
There's a bunch more that don't have indexers too.