I am always glad to fix such bugs before a release (I am about to prepare 2.2.22).

It worked! You were right!

Thank you for your prompt help. It's much appreciated.

I see. Thank you @werner . For clarity could you please link the patch that was not backported to 2.2.?

But @werner what's the value $TERM *supposed* to have? When gpg is invoked straight by Gnome? I can run the command sh -c 'env | grep TERM > ~/gnome-term.env' in Gnome's "Run Command: interface and then the file ~/gnome-term.env says TERM is set to nothing (It is set, but the contents is a "" string).

Unfortunately I've had some trouble compiling the latest git version of GnuPG for NixOS - I got this warning which turned out to be a blocker:

I take some of my words back - using or not using MOZ_ENABLE_WAYLAND=1 doesn't make a difference eventually - If Firefox is launched by Gnome and not gnome-terminal, pinentry fails to launch with and without MOZ_ENABLE_WAYLAND.

Wow thanks for the great explanation! I've always wondered what is the relationship between gnupg and other secrets services. Personally, although Gnome's / KDE's secrets services offer better UX out of the box, I've always preferred gpg's agent because I can control it better from the command line and hence customize it's behavior. The only use I have for gnome-secrets service is for a few passwords I always want them to be cached (because I obtain them in systemd timers+services). Do you think Gnome / KDE will ever plan to _use_ gpg-agent, instead of reimplementing it?

Works! I still wonder though: How come my system / gpg agent has all of a sudden started using the external cache? Is this a new feature of gpg-agent? And what is the meaning of this message:

BTW, since I start my X session with startx, these are the relevant parts I have in my .xinitrc:

So my gpg-agent.conf file looks like this now: