Board Thread:Support Requests - Getting Technical/@comment-5301680-20170823090938/@comment-27345308-20170823092315

You're looking at the wrong file, the main page name is being taken from here. Where are you seeing that fallback being used? It could be used because:
 * 1) Main page name inside MediaWiki:Mainpage is invalid
 * 2) Main page isn't in main namespace (this actually happens on my test wiki, and I commented on the pull request that was supposed to fix "Main Page" being the default link for all wikis but they didn't properly test that case or respond to my comment before merging the pull request)