Tiles don't have protos and therefore proto Ids don't exist either, that's why format is different.
In case of tiles it's filename prefixes, for example "bld" will add everything in tile directory that starts with "bld": bld001.frm, bld002.frm, and so on. Subtabs of tiles are created and named automatically, it's impossible to control it with AngelScript (which sucks, but it is what it is). The only reason the tiles are in tabs.cfg at all, is because I wanted at least the floor and the roof tiles to be in separate tabs, which cuts the mess by half.