The 184.108.40.206 release is an open beta test of the Mac and Linux versions of Terraria. It contains no game content changes, only modifications to the game engine for compatibility with Mac and Linux systems. As such, this release has no formal changelog.
220.127.116.11 was an optional update while still in development, requiring players to opt in before it would be installed. The beta was distributed through Steam's beta functionality; as such, only Steam copies of Terraria could opt into the 18.104.22.168 beta. Mac and Linux users who chose to enter this open testing phase were asked to join the Open Beta Testing Feedback Group on the forums to provide feedback and bug reports.
While 22.214.171.124 was released early due to the lack of sensitive "spoiler" content in its prerelease, open betas are not expected to become standard for testing of future updates.