Google has once again updated the relatively new documentation around Site Names in Google Search, this time to clarify that www and m-dot prefixes for domain names are generally considered root domain names for Site Names in Google Search.
The site name documentation added two more "supported" examples to the technical guidelines list. These two new examples include https://www.example.com and https://m.example.com. Google said these and the non-www are considered to be a domain-level homepage.
Here is a screenshot from Glenn Gabe on Twitter of the two new lines:
Here is what it looked like previously:
Forum discussion at Twitter.
