Some kind of duplicate glitch when editing navigation menu permissions
I haven't found the source, but for example
- Admin - customize - Navigation menu.
- Go to add or edit one.
- In the permissions field start typing "edit mess" to get the edit message templates permission. Behold:
- Note also the description on the second one is for a different permission.
This also happens if you start typing "system". My guess is it's related to the relatively recently added concept of "implied permissions", because note that those super permissions don't appear in the list, e.g. administer civicrm data isn't a possible choice for a navigation menu permission.