404 on firmware configuration page on the wiki
https://wiki.gnome.org/Apps/Games/Documentation#Firmware_configuration
Flatpak version: ~/.var/app/org.gnome.Games/config/gnome-games/platforms/[PLATFORM]/system, where [PLATFORM] is the corresponding platform as defined here (i.e. "TurboGrafxCD").
The "here" links to https://gnome.pages.gitlab.gnome.org/retro-gtk/libretro-core-descriptor.html#Known_Platforms which is not found.