On Sun, 22 Apr 2018 at 11:27 Terry Reedy <tjreedy@udel.edu> wrote:

Does github allow repository owners to send email directly to people who
have submitted PRs or at least, people with commit privileges (in this
case, those whose have done particular merges)?

No. People have to provide explicit permission to expose their email address. Otherwise the best we have are @ mentions in a comment.