Simple breakdown of BIP91: It’s simply the miners deciding to activate BIP148 among themselves before August 1. Once they activate BIP91, blocks not signaling SegWit will be orphaned, JUST LIKE UNDER BIP148. Then SegWit will activate under the original/Core BIP141–JUST LIKE BIP148.

They hated BIP148 so much, that they "decided" to activate it early.

Submitted July 18, 2017 at 03:57AM by Lejitz
via reddit