Sounds are only volume adjusted from the original The One Who Watches mod by Pixel_Coder on CurseForge.
You do NOT need the mod for this pack to work. It replaces vanilla sounds only.

The One Who Watches mod:
https://www.curseforge.com/minecraft/mc-mods/the-one-who-watches

I just wanted these sounds as cave noises because I hate myself =)
They also play in the Nether, so have fun =)