Decals01 - Subtractors
These are normal and parallax mapped 'subtractors', meaning, it appears as if they take material away from the underlying surface.
Decals02 - Subsets
Similar to 'subtractors', these are also normal and parallax mapped and seem to take material away, but unlike decals01, they fill in a 'subset' as well.
Some of these are based on HardOps assets.
Info01 - Info Decals
Infographics, warnings signs, typography etc. Most of these are based on real aircraft decals.
Paneling01 - Panel Decals
These are normal mapped panel decals. They are imported automatically by Decal Slice and Decal Knife, based on the default paneling you choose in the pie menu..
You can drop these panel decals into the scene manually, if you want to change the panel decal type by applying a different panel decal material or if you want to manually extrude panel lines on a surface, instead of using Decal Slice or Decal Knife to create panel decals.