"Spiral wound" means standard brake housing, not the "compressionless" shift housing which should never be used for brakes. So, yes, they mean standard brake housing. There is compressioless housing rated for brake use and that's what they want you to use for the housing run after the double-end ferrule.

Double end ferrules are used to connect two sections of brake housing and are available at your LBS or on-line. Here is one source: Jagwire Double-Ended Connecting Ferrule > Components > Cables & Housing > Brake Cables & Housing | Jenson USA

TRP wants you to use two joined sections of housing instead of a single full length housing run so the majority of the housing run is compressionless and gives a firmer brake action.