There's a game that, while I will admit that I don't really have an interest in playing, isn't working properly because it's trying to default to a GPU driver that isn't even loaded ( and possibly not even installed). The game is called Zbridge and it's standalone app is only distributed through Flathub. For some reason, it's trying to default to using "iris" even though the only GPU driver that's loaded is "i915". I have confirmed this with this:

j@j-Latitude-E7470:~$ lspci -k -s 2
00:02.0 VGA compatible controller: Intel Corporation Skylake GT2 [HD Graphics 520] (rev 07)
	DeviceName:  Onboard IGD
	Subsystem: Dell Latitude E7470
	Kernel driver in use: i915
	Kernel modules: i915

But the game, on top of giving some other errors I've found to be trivial, still tries to load iris by default for some reason:

j@j-Latitude-E7470:~$ flatpak run club.zbridge.zbridge
[2:1229/172053.425891:ERROR:bus.cc(407)] Failed to connect to the bus: Failed to connect to socket /run/dbus/system_bus_socket: No such file or directory
Gtk-Message: 17:20:55.221: Failed to load module "xapp-gtk3-module"
[2:1229/172056.788306:ERROR:bus.cc(407)] Failed to connect to the bus: Failed to connect to socket /run/dbus/system_bus_socket: No such file or directory
[2:1229/172056.788423:ERROR:bus.cc(407)] Failed to connect to the bus: Failed to connect to socket /run/dbus/system_bus_socket: No such file or directory
MESA: error: Failed to query drm device.
glx: failed to create dri3 screen
failed to load driver: iris
[41:1229/172103.010356:ERROR:viz_main_impl.cc(196)] Exiting GPU process due to errors during initialization
MESA: error: Failed to query drm device.
[2:1229/172118.159439:ERROR:gpu_process_host.cc(989)] GPU process exited unexpectedly: exit_code=512
MESA: error: Failed to query drm device.
[2:1229/172133.299896:ERROR:gpu_process_host.cc(989)] GPU process exited unexpectedly: exit_code=512
MESA: error: Failed to query drm device.
[2:1229/172148.425964:ERROR:gpu_process_host.cc(989)] GPU process exited unexpectedly: exit_code=512
MESA: error: Failed to query drm device.
[2:1229/172203.465700:ERROR:gpu_process_host.cc(989)] GPU process exited unexpectedly: exit_code=512
MESA: error: Failed to query drm device.
[2:1229/172218.491001:ERROR:gpu_process_host.cc(989)] GPU process exited unexpectedly: exit_code=512
MESA: error: Failed to query drm device.
[2:1229/172233.517237:ERROR:gpu_process_host.cc(989)] GPU process exited unexpectedly: exit_code=512
[2:1229/172233.517295:FATAL:gpu_data_manager_impl_private.cc(448)] GPU process isn't usable. Goodbye.

I have found a temporary solution by running export MESA_LOADER_DRIVER_OVERRIDE=i915 but as far as I can tell, I shouldn't have to do this because it should just be defaulting to the driver that's already loaded. If this is an issue with the app itself, I am going to submit a bug report but I want to make sure this issue isn't on my end before submitting one.