The file system interface exposes the editor's built-in and contributed file system providers. It allows extensions to work with files from the local disk as well as files from remote places, like the remote extension host or ftp-servers.
Note that an instance of this interface is available as
Check if a given file system supports writing files.
Keep in mind that just because a file system supports writing, that does not mean that writes will always succeed. There may be permissions issues or other errors that prevent writing a file.
The scheme of the filesystem, for example
true if the file system supports writing,
false if it does not
support writing (i.e. it is readonly), and
undefined if the editor does not
know about the filesystem.