* Better wipers: More powerful or more sophisticated wiper systems were available.
* Different glass: Options might have included tinted glass or glass with better clarity.
* Rear window defogger: This was an option, especially valuable in colder climates.
* Clear lenses: Some lighting options might have had clearer lenses compared to standard options.
If you've encountered "visibility group" in relation to a specific 1968 Mustang, it's likely a term used by a particular seller or restoration shop, and doesn't reflect official Ford terminology. To understand what it actually encompasses, you'd need to see the specific description from that source.