BIP 148, documented in BIP-148, is a user-activated soft fork (UASF) that pressured miners to support SegWit. After a specified deadline, nodes enforcing BIP 148 would reject any blocks that didn’t signal readiness for SegWit, effectively risking a chain split if miners failed to comply.

This maneuver underscored the power of nodes in Bitcoin’s governance, highlighting that miners alone don’t decide consensus rules. BIP 148 played a key role in the 2017 activation of SegWit, ultimately succeeding in forcing miner compliance. While contentious at the time, it became a historical moment demonstrating community-driven consensus in Bitcoin’s decentralized ecosystem.