In short it is a collection of my favorite textures of my own that shape the minecraft world in some way. like:
stone, cobblestone, granite, diorite, gravel, rails, ladder, torches, lever, dirt, darker netherrack, yellower sand, moon-like endstone etc.

Included are some Vanilla Tweaks: https://vanillatweaks.net/picker/resource-packs/
and my favorite glowstone texture from redmatazz: https://www.planetminecraft.com/texture-pack/prettier-glowstone/

It also includes emissive textures for both CTM and Optifine