> I don't see that tab, so either the docs are out of date, and it's called something else now, or it's not on all accounts/all repos.

Correct. It's only for certain plans like GitHub Team and Enterprise Cloud.

The weird part about this e-mail is that they said they recently left some organizations because "the tone of the paid services" increased. So either they're still a member of one of these organizations, or GitHub mistakenly sent the e-mail to past members?