Figured it with Gemini.
https://github.com/po5/chapterskip
mpv\script-opts\chapterskip.conf
# This defines one single category called "sponsorblock"
# The pattern matches any chapter title that STARTS WITH "[SponsorBlock]:"
categories=sponsorblock>^%[SponsorBlock%]:
# This tells the script to skip any chapter matching the "sponsorblock" category
skip=sponsorblock
was there a better option?