Beginning today, repository admins must invite you to their repository and you must accept the invitation before you can start collaborating. Repository invitations let you decide whether or not you want to join as a contributor.
Collaborating with other developers is one of the best parts of open source on GitHub, but getting there hasn’t always been a happy journey. Previously, anyone could automatically add other developers to their repositories without explicit permission. This model openly provided some users with opportunities to harass members of our community by inviting them to offensive or attention-seeking repositories.
With repository invitations, every GitHub user can accept or decline requests to collaborate on someone else’s repository. Should those invites go too far—due to spam or malicious content—you have the option to block the user sending them. Blocked users cannot invite you, fork your repositories, or comment on your activity.
Repository invitations are a big step forward in providing you with more control of your experiences on GitHub. We’re excited to encourage more positive and respectful interactions between our users and look forward to future opportunities to further improve our community.