Play with the features of modern versions but with the nostalgia, stability and smoothness of 1.12.2, plus some extra things in the "Vanilla+" style.
Some backported blocks for Minecraft 1.12.2, plus some extra original new blocks.
Sculck Catalyst and Sculck Block backported to 1.12.2.
The flower from 1.21.5 backported to 1.12.2.
Purple vines which grows from the underside of End islands, 1.12.2.