What are these files?

[DrSquishy]

I have had extreme trouble with getting any non tf2-base textures to actually get packed into my map, but when trying again with VIDE, i saw it already had a (texturename)vvt_patch.vmt in the bsp already. What are these? are they like the normal texture or what?

 

[B!scuit]

I think vvt_patches are textures that tell a displacement how a blend texture is blended
they should be in the first few lines of vbsp's output in your compile logs
vbsp.exe packs them by default

 

[fubarFX]

so, a lot of materials are created at compile time and only exist inside your bsp. There's a few instances where this happens, but you never have to worry about packing them because they are added at compile by vbsp.exe. I believe blend materials and water materials are the main causes.

in this case, read up on the patch shader https://developer.valvesoftware.com/wiki/Patch
Vbsp creates patch materials which it relies on instead of simply using a material directly, it essentially exists to override properties of existing materials when vbsp judges it's necessary to do so.