I could not find any documentation for it. See API response for an example: https://en.wikipedia.org/w/api.php?action=query&titles=File:Logo%20Google%202013_Official.svg&redirects&format=json&formatversion=2
Topic on API talk:Get the contents of a page
Hi @Mitar, Based on the code history (Gerrit change 304874), it looks like the "known" flag is used for pages where the content is being mirrored from another wiki, such as file pages from Wikimedia Commons or global user pages from Meta-Wiki.
Thanks! Should this be documented somewhere?
Yes, I think so. I've added a note to API:Query#Example_3:_Missing_and_invalid_titles since that's where "missing" is also discussed.
Awesome! Thanks!