I have a Debian buster system where I am logged in to the local GUI and also logged in over ssh. I need to sign something with gnupg over ssh.
Unfortunately I get no prompt for a passphrase on my ssh session, I suspect the prompt is being shown graphically in the GUI, but since I'm not in front of the machine right now I can't check.
In the past I have achived this through killing the gpg agent and starting one manually, but that doesn't seem to work anymore. The agent tells me it is already running. From some searching it seems that a systemd user service may be responsible for this.