The term "Mac Exclusive" in the search query is likely a misinterpretation of the release notes or download page formatting. Version 1.5.12 was released for both:

Always verify checksums of legacy software. Only download from verified DJ forums or Serato’s official legacy link archive to avoid malware.

: Support for Beatsource LINK and Beatport LINK including an Offline Locker to store tracks for playback without internet.