Feature request: Restricting moving/copying files/text between qubes

Thank you, apparatus, for your quick reply. I did not work with qrexec policies before but it sounds very interesting. Editing a text file is feasible but very technical. I rather thought of a GUI solution since a non-tech user could easily make mistakes when editing files (I see that your first link points to the developer documentation). Is there already a GUI solution for editing qrexec policies? I found this:

Would it be worth to mention (and link to) the GUI policy manager on the pages How to copy and move files | Qubes OS and How to copy and paste text | Qubes OS ?

PS: TBH, I screwed up my Qubes installation and did not have the time to reinstall it yet. So, currently, I write my ideas by using my memories and I cannot reproduce steps.