In January 1986, Apple and Sun Remarketing (then called Sun Data) jointly announced an agreement transferring responsibility for service and support of the discontinued Apple /// to the Logan, Utah computer reseller. Apple had removed the /// from its price list the previous September after quietly discontinuing development on the same day it rolled out the Apple IIc to great fanfare in 1984. In addition to selling new and refurbished Apple /// hardware, as well as Apple’s line of business software for the computer, Sun would also sell manuals and documentation. Once the cache of original printed materials was depleted, Sun began selling photocopies with new cover artwork.
This is Sun’s version of the UPIC manual. As far as I can tell, the only difference from Apple’s manual (other than being a photocopy) is the new cover, so unless you’re a Sun Remarketing fan or a completist, I’d recommend just grabbing a PDF of the original here.