It’s in the firmware category, i.e. it comes from LVFS. It’s neither a Flatpak nor a DEB/RPM/… package. Many of these, I believe are actually exe
files for DOS (happy to be corrected on this, it’s a while since I last read Richard Hughes’s blog).
Iirc, GNOME Software is plug-in-based and the Flatpak plug-in is just one of the plug-ins.
I think GNOME Software uses some
fwupd
library rather than the straight-up command-linefwupdmgr
, but yeah, basically.