List of steps to reproduce (step by step, including full links if applicable):

• Switch to the Minerva Skin
• Submit article to Google Search Console for indexing
• See Issue with title

What happens?: Titles for the main page of a wiki become visible on Google as " — Wiki Name", with nothing preceding the dash. This looks pretty silly, and makes wikis look less reputable than they are.

What should have happened instead?: Simply, the site name should show such as "Wiki Name"

Software version (if not a Wikimedia wiki), browser information, screenshots, other information, etc.: MediaWiki 1.37. Basically, what happens is I believe that the value passed to "pagetitle" is the message stored at MediaWiki:Mobile-frontend-logged-in-homepage-notification, which happens to be "Welcome, $1" if this is left unchanged. Now, when Google crawls the page using Googlebot, it doesn't pull "Welcome, Googlebot" or anything like that, it just pulls a blank string.

This causes issues when the page is indexed as Google will index the page as " — Wiki Name" as it doesn't understand "Welcome, {{1}}" therefore just blanks it out. Of course, this can be changed by editing MediaWiki:Mobile-frontend-logged-in-homepage-notification, but there should be an option to just have the sitename display instead. I think this should be done by default too, as it causes a lot of issues for those who don't know what said MediaWiki message is causing the issue.

As you can see from the image, it looks very odd. One could perhaps replace the message at Mobile-frontend-logged-in-homepage-notificaiton with their sitename, but this would look silly "Test Wiki - Test Wiki".

The Timeless skin handles this perfectly, and displays just "SITENAME" on the main page — this is how Minerva should do it too,