Looking at this page in the documentation. The description of “entry-point-name → author” says to “Use a multi-line list if there is more than one author.”
What exactly is a “multi-line list”?
Should it be an actual list, containing mutliple strings?
It should be a string if there is 1 author, and a list for multiple. I’m guessing the multi-line recommendation is to deter from a comma-separated name1, name1 or bracketed list [name1, name2] for readability.
I’m not aware of any validation for authors in role argument spec. The argspec options are validated against the available variables when running the role.