Steps to replicate the issue (include links if applicable):
What happens?:
At the top of the page is a empty line, then the various pagetools/tabs, then another line
What should have happened instead?:
Only the bottom line should be visible, as there is no title for the top line to underline.
This is visible because setting [[Mediawiki:Mainpage-title]] to blank sets style="display:none" on the h1 element, but does not remove the border-bottom: 1px solid #a2a9b1; from .vector-page-titlebar which is set on the parent header element