This is fixed in the next release.
In 4.0.16, there is a new permission under Special Page Permissions "Can edit and rename Special pages?"
This permission provides the Edit tab, which lets you change the following:
- Prefix
- Title
- Icon
The permission also provides the Synonyms tab.
The Prefix and Title here might only change the Special page's URL. If there was a phrase for the title, that phrase is still used as the heading when you visit the page.