Language server
The one exception to “nothing is bundled.”
typescript-language-server needs a real TypeScript install to run against and has none of its own, it happily uses a project’s own node_modules/typescript when present, but a plain JS-only folder with no package.json has nothing for it to find. Coder ships its own copy of tsserver.js as a last-resort fallback, used strictly after checking for (and not finding) a workspace-local install, so a project pinning its own TypeScript version is never overridden by Coder’s bundled copy.
Debugger
See Debugger for the debugger UI itself.