Breyer has actually been writing on these issues for quite some time; see for example his article "The Uneasy Case for Copyright: A Study of Copyright in Books, Photocopies, and Computer Programs" [0] -- published in the Harvard Law Review in 1970. His overall body of work demonstrates a pretty good understanding of the underlying technical issues, and he has been a reliable ally on the bench in this area.

[0]: https://www.jstor.org/stable/1339714?seq=1