Open the https://en.m.wikipedia.org/wiki/Main_Page page without logged in, you will see the " - " is the beginning of the title.
This problem applies to Wikipedia in all languages.
Registered | Unregistered |
It looks due to a bug from https://gerrit.wikimedia.org/g/mediawiki/skins/MinervaNeue/+/4351eba58ba96b7a29b209f1ea915936e895b27e/includes/Skins/SkinMinerva.php#536, if the visitor is an unregistered user (not logged in), $pageTitle = '' and pass to $out->setPageTitle.
This may be a duplicate, but I can't find it.