Ports all features of 1.17.1 Fabric version to 1.16.5, plus some tiny changes that haven't arrived 1.17.1 yet (but will do in a few days):
# Fixed most mobs on Heavenly Challengers - also added extra mobs for extra difficulty.
# Fixed treasure loot tables on Heavenly Challengers.
# A lot of tweaks were done to loot tables. A lot of them contain exploreration maps.
# Sent everyone who asked for a 1.16.5 backport to hell.
# Added a safecheck so flying structures don't attempt to generate above worldheight.
Keep in mind 1.17.1 is still the main version.
Fabric API and Cloth Config API are still required.