Is it possible to read and edit the "Xtra" atom metadata in an MP4 file?

To clarify, if you add/edit some specific metadata tags (e.g. "Directors") in an mp4 using some particular Microsoft apps e.g. Windows 10 Explorer (via right-click >> Properties >> Details tab >> "Directors" tag), it is stored in the "Xtra" atom / box of an mp4 file, and not the regular "meta" atom.

In contrast, the regular ID3 "Director" tag (which is seen as "©dir" in a hex editor) is stored in the "meta" atom, but what Windows Explorer calls "Directors" in the Details tab is stored in the "Xtra" atom.

This "Directors" tag edited by Windows Explorer can be seen as "WM/Director" in a hex editor; whereas, ExifTools calls it "Microsoft:Director". As far as I have investigated, all tags in the Xtra atom start with a "WM/" e.g. WM/Conductor, WM/Publisher, WM/EncodedBy, WM/SubTitle, WM/Producer, etc.