Hi!
You can find the source for 0.4.5.2-alpha at the usual place, at https://dist.torproject.org/ . It fixes a few bugs in 0.4.5.1-alpha: everybody running 0.4.5.1-alpha will probably want to upgrade.
If you don't package alphas directly, that's okay, but please at least make sure that this version builds and runs okay on your target platform: we've made some changes in the build system that should really be tested before we call this series stable. (It's always easier to fix things while we're still in alpha.)
You can read the changelog at https://gitweb.torproject.org/tor.git/tree/ChangeLog?h=tor-0.4.5.2-alpha .
I'll be sending out official announcements soon.
peace,
tor-packagers@lists.torproject.org