In Synfire, what does the > symbol in a figure represent?

That's the indicator for the Look Ahead property of the segment.

If at measure 2 in the example below a chord change happens to occur, the segment will already render it, although the next chord is not yet playing (useful for upbeat and pushed rhythms where the instrument plays ahead of time).

The example picture also includes the Hold property, which makes the segment continue to play the same context regardless of subsequent chord changes (useful for chord strumming, to avoid a "page break" inside a segment).

Andre

(look_ahead.png)