Thanks!

But, I already have the last Yuzu Flathub flatpak installed on one computer and the last Ryujinx Flathub flatpak installed on another. "flatpak upgrade" does not remove them even if they were removed from Flathub. I just get:

  Info: app org.yuzu_emu.yuzu branch stable is end-of-life, with reason:
  This application is no longer maintained. See https://yuzu-emu.org/ for details.

But, I want to archive these two apps to make sure I can migrate them around computers for all eternity. :D

What does the steps look like then?