you can create them in the material editor, no coding required, its an visual interface where you can connect different nodes to an output whats done here is called channel packing, where you fit as much information in as few textures as possible while still retaining full qualitymost likely they thought they don't need a…
This one looks baked (has padding), and those channels don't look like seperate maps (weird artifacts, flat). So I would guess this is actually a 2-channel/"yellow" normalmap. These are often the output of game rips because you get all the post-compressed stuff, not the original input maps. You're focusing too much on the…
I see. I thought that was the standard, specifically in Unreal. All the guides seem to show it. Although, I don't believe I've set up a custom shader before. Do you have to code those...?
I dont use unreal but there's a shadergraph. You just connect little behavior boxes. It doesnt require any coding skills or shader knowledge to just swap channels around. But just repack the maps the unreal way if it's easier.