"Only the parts you need" is a GURPS podcast hosted by Legendsmith and EnragedEggplant. This episode's topic is vision (EnragedEggplant).
Transcript - https://enragedeggplant.blogspot.com/2022/04/everything-about-vision-in-gurps.html
Pizard's Stuff - http://panoptesv.com/RPGs/Ads-n'-stuff/ads.html
Kromm's post on darkness - http://forums.sjgames.com/showpost.php?p=783710&postcount=14
Alternative Stealth - http://forums.sjgames.com/showpost.php?p=1329938&postcount=8