There is very little officially published about this.
It appears that Github invited a senior ICE official to speak at one of their events.
This, however remote, affiliation was deemed inappropriate by many, forcing Github to rescind the invitation.
I believe it’s “immigration and customs enforcement”.
Yet the very same folks were totally fine under Obama, who deported the largest number of illegal aliens ever. The whole anti-Trump hysteria used to crack me up, but it’s getting tiresome.