The home page for Google+ has a "Join Google+" button near its upper-left corning. Clicking the button leads to Google Account authentication, and then a modal with inputs for entering a "given name" (first name or forename) and "family name" (last name or surname).
When I enter my name, I get an error:
The name you entered doesn't seem to meet our Names Policy. Check it over and try again.
However, the linked "Names Policy" seems to say nothing of what is required or forbidden for a name.
I've searched the web for more information, but all I find is news articles announcing when Google dropped its "real names policy".
Can anyone link to documentation or testing that would show what rules might be in effect, such as alphabets or lengths?