The streaming part or the downloading/looking at code? You can look at leaked source code for educational purposes in most places (not legal advice). As far as

The streaming part or the downloading/looking at code? You can look at leaked source code for educational purposes in most places (not legal advice). As far as I understand leaks are commonly used in vulnerability research for example (if the bad guys can use it so can bug hunters). Streaming copyrighted material is a separate issue - but using it for "criticism, comment, news reporting, teaching" should fall under fair use, no?