I love the music right as Wedge and Lando fly into the main reactor chamber. Was this particular sequence ever released in any of the multiple iterations of the soundtrack? I know "The Battle of Endor III" has a subsection called "The Main Reactor" but I don't think it contains that short bit of music.
Here's a clip for reference in case you didn't have the entire movie/score memorized.
That piece is tracked in from EMPIRE STRIKES BACK, from the "Losing A Hand" sequence of the climax at Cloud City, specifically when Luke is being rescued by Leia and the gang.
Yes, it's tracked from ESB, and available on several releases of that score.