Disable Gnome Keyring SSH agent in (X)Ubuntu

Disable gnome-keyring-ssh

# Disable Gnome Keyring SSH agent in Ubuntu
# To allow using ssh-agent from OpenSSH, mainly because
# gnome-keyring does not like EC-type SSH keys

# as regular user (for which to disable):
systemctl --user mask gnome-keyring-ssh.service

pam-auth-update
# and disable "GNOME Keyring Daemon..."
# which probably also disables automatic keyring unlocking on login

echo X-GNOME-Autostart-Enabled=false >> /etc/xdg/autostart/gnome-keyring-ssh.desktop

# if using XFCE4:
xfce4-session-settings
# on 'Advanced' tab disable 'Launch GNOME services on startup'