@mitu i dont think its a dependency. it is something that the guys who made OpenMW, built to help with the running the game
this is what quicksliver said about in on the forum page about installing OpenMW
Also a couple notes about running OpenMW on the raspberry pi. You cant use open scene graph from the apt repository, it has to be manually compiled against OpenGL NOT OpenGL ES otherwise the game will not run. OpenMW devs recommend using their fork of OSG for better performance though that is not strictly necessary (I used their fork and it works great https://github.com/OpenMW/osg). The following cmake arguments can be used to prevent building unneeded OSG plugins and prevent bloat