The latest musl source is always available via the git revision control system. Efforts are made to keep the master branch in a state that not only compiles and works, but that works at least as well or better than the latest release.
The following command can be used to checkout a copy of the musl git repository:
$ git clone git://git.musl-libc.org/musl
Source and revision history are also browsable online via cgit.
Through the 0.9 series, release versions of musl are generally timed so as to make fixes for major bugs available in release form as soon as possible while leaving ample time for testing after significant invasive changes.
Current release is 0.9.15.
Earlier versions of musl from the alpha and beta series (0.5.0 through 0.8.10) have been moved to a separate page.