No mystery and I don't need to guess
I have been asked for Cavatina many, many times over the years and they certainly don't mean Tansman!
If you play in public, Cavatina (Myers) is one of a handful of CG 'standards' that the general public will have heard of.
It would be a fairly straightforward task to transcribe this by ear (although you'd have to make sure its the solo guitar version you are listening to and not the dubbed 'duo' version Williams recorded for the film) due to the tempo, the clear separation of the notes and limited options for positions of the chords. However, its much quicker to simply get the music and the JW arrangement has some fingering too.