When deleting orphaned attachments the following text will be added as action to the admin log:

{Orphan Files deleted
» 2 f8b5832cb004f12167e00eb649c26e9a.jpg{color:red}}

This is caused by line 1983 in includes/functions_admin.php:

$log[$i]['action'] = (isset($user->lang[$row['log_operation']])) ? $user->lang[$row['log_operation']] : '{' . ucfirst(str_replace('_', ' ', $row['log_operation'])) . '}';

I tried simply removing the appended brackets and the log still seems to work fine.