When you would want it

This is what replaces having to install an extension for every language. If your language has a language server, you can use it here.

Where to find it

All Features → Additional language servers
Settings

What you get out of it

Any language with a language server becomes first-class in one line.
No extension ecosystem to grow or wait on - the standard protocol is the plugin format.

How to use it, step by step

Open Settings and find Additional language servers.
Write one line per language as 'language: command' - 'zig: zls' or 'elm: elm-language-server --stdio'.
Click away from the box; it takes effect immediately.
Open a file in that language: the server starts and full intelligence arrives.

Why this beats the usual way

Marketplace extension per language is a lottery - coverage is patchy and quality varies wildly. One line to a standard server gets you the same intelligence everyone else has, from the same tool.

Find it in Universal Search

Additional language servers · Languages