It's based on Monaco Editor, which is the open source base of VSCode - you can see the full list of supported languages by clicking the dropdown on the bottom r

It's based on Monaco Editor, which is the open source base of VSCode - you can see the full list of supported languages by clicking the dropdown on the bottom right (similar to VS code: https://code.visualstudio.com/docs/languages/overview#_change-the-language-for-the-selected-file https://code.visualstudio.com/docs/languages/overview#_chang...)