On Github, someone told me that there is someone else in the Gnome
design team working on mockups for a new document manager / scan
application[1][2]. It looks quite similar to an application I've been
working on for a while: Paperwork.
Website: https://openpaper.work/
Sources: https://github.com/openpaperwork/paperwork/# readme
Demo: https://www.youtube.com/watch?v=RMazTTM6ltg