VoxeLibre/mods/CORE/_mcl_autogroup
..
README.txt
depends.txt
description.txt
init.lua
mod.conf

README.txt

This mod automatically adds groups to items based on item metadata.

Specifically, this mod has 2 purposes:
1) Automatically adding the group “solid” for blocks considered “solid” in Minecraft.
2) Generating digging time group for all nodes based on node metadata (it's complicated)

See init.lua for more infos.

The leading underscore in the name “_mcl_autogroup” was added to force Minetest to load this mod as late as possible.
As of 0.4.16, Minetest loads mods in reverse alphabetical order.