Quick disclaimer - Don't count on any Types to save you here. Sure the files are called .ts but :oof: It's a mess.
You'll see lots of stuff that ctrl/cmd + click'ing on will just lead to nowhere, and yet it still works somehow.
This will show up in packages/client/src/router.ts
This will show you the route and then the appropriate packages/client/src/pages/x.vue that the code lives in.