if (!array_key_exists($this->plugin, $defaultPlugins)) {
// TRANS: Client error displayed when trying to enable or disable a non-existing plugin.
$this->clientError(_('No such plugin.'));
if (!array_key_exists($this->plugin, $defaultPlugins)) {
// TRANS: Client error displayed when trying to enable or disable a non-existing plugin.
$this->clientError(_('No such plugin.'));