They have a "Measures to reduce spam" section outlining that : https://hacktoberfest.com/participation/#spam
Also seems that projects must now opt-in by labelling themselves with "hacktoberfest-accepted”.
Also seems that projects must now opt-in by labelling themselves with "hacktoberfest-accepted”.
"hacktoberfest-accepted" is a label for pull requests you want to mark as accepted but don't want to merge yet (a pull request has to be merged OR approved OR have this label to count).