There are two things that are called "endurance saddles."
The first is the English style endurance saddle, most often seen in the UK and western Europe. This saddle looks like an English saddle, but has a slightly higher cantle, a lot of extra rings to attach things to it and very obvious knee rolls to help keep the leg in position on long rides.
In the rest of the world, an endurance saddle is a lightweight, closer contact western saddle that often lacks a horn. (I speak from experience - these saddles are amazing and my first choice for extended trail rides).