It's a little bit more than only an editor. E.g. it contains the complete framework for custom languages with syntax highlighting, auto completion, annotations, etc. You can easily plug in support for your custom languages there.
What it doesn't contain compared to VsCode is multiple panes, file management, etc.
You can of course build file management on top of the base Monaco component. Monaco itself provides only APIs to set or retrieve the content of a monaco editor widget. You can then build some kind of filemanager on top of it which loads file contents from whereever and puts them into an editor instance.
What it doesn't contain compared to VsCode is multiple panes, file management, etc.