I don’t have openssh nor any keyring installed in my system, I use xfce if that matters.
A file is always created inside ~/.ssh/agents/ at boot, I can delete it manually or it gets deleted when I run ssh-agent -k (I didn’t install anything related to ssh, but the client is present in the system)
The only reference I found is in KeePassXC, in Settings - SSH Agent the file is listed as SSH_AUTH_SOCK value, the SSH Agent is disabled. Not sure if it’s related or not. I searched around but found nothing about this issue.