^Read the track listings for yourself, as posed earlier in this thread or all in one place here
. They list the different versions of the main title that are included in the set. In addition to the pilot versions, there's the "electric violin version" on Season 1, Disc 2, the Steiner-arranged "cello version" on S1D3, the 2006 re-recording of the cello version on S1D5, the "soprano version" on S2D1, an "enhanced stereo" version of same on S2D2, the 2006 soprano version on S2D5, the third-season stereo version conducted by Wilbur Hatch on S3D1, the mono version of same on S3D3, and the 2006 version of same on S3D5. Plus the corresponding versions of the end title on the same discs.
As they've said, this set contains every single note of music written and recorded for TOS, including alternate versions -- save only "I'll Take You Home Again, Kathleen" and the J. Peter Robinson substitute cues for "Goodnight, Sweetheart" from that '80s syndication release of "City on the Edge" that couldn't get the rights to the song.