can you trace the wires? they are an add-on of some sort so saying what they are for is impossible.... could be anything from an amp for a stereo to LPG install thats no longer there to air horns/alarms, lights, central locking systems..anything really
I'd have a go at tracing the wires and until I knew what they did I'd
leave the fuse OUT as it might make something live somewhere that could drain the battery/cause a short or worse.....