@hendrikboom3 @gnu_texmacs I'm not familiar with WordPerfect but if I want to view/edit discrete parts of the data tree of a TeXmacs document, the program can display the tree in whole or in part.
A TeXmacs document tree is saved as XML-like text but editing the markup by hand with an arbitrary text editor (as is often done with LaTeX) is not supported.
The pictured example: https://gitlab.com/baltakatei/bk-2021-07-1/-/blob/fbe3af98e869638bff58e6ab43391ec48f9742b3/src/c8.tm#L967