Originally Posted by Gudy
It fits rather snugly, so to speak. In fact, if you've read all six books in the series, the novella in The Warmasters offers nothing new, as it is essentially the extraction of two plot threads from one of the later books in the series (I forget which, but I'm tempted to say book 5).
Actually, the novella in The Warmasters
was written first. Eric Flint decided to incorporate it into the final book of the series later on, because he felt it just fit there really well.