Command names are now prefix-matched, so you can use asciinema r instead of asciinema rec, asciinema st instead of asciinema stream, asciinema se instead of asciinema session, asciinema u instead of asciinema upload, etc.
When recording to a file inside a non-existing directory, that directory (and its parents) is now automatically created (#679)
Packaging-related changes
Version constraints of the dependencies have been relaxed to make distro packaging slightly easier (in theory, we'll see)
Removed 168 transitive library dependencies (since 3.0.0-rc.4) by removing duplicate deps and reimplementing a thing or two (71 LOC replaced 73 deps on its own)
The generated man pages are now more informative and complete
Bug fixes
Fixed a memory leak and a race condition in streaming