Changing line 48 in admin-ui.php from
$hook = add_management_page( 'Keyring', 'Keyring', 'read', 'keyring', array( $this, 'admin_page' ), '' );
to
$hook = add_management_page( 'Keyring', 'Keyring', 'read', 'keyring', array( $this, 'admin_page' ), null );
appears to clear it. The last parameter needs to be an integer or null.