This directory contains two important files for all of Nektar++: NektarUnivConsts.hpp and NektarUnivTypeDefs.hpp.
The file NektarUnivConsts.hpp contains various default constants used within Nektar++ as seen here:
The file NektarUnivTypeDefs.hpp contains the low level typedefs such as: NekDouble, NekInt, OneD, TwoD, ThreeD, FourD, and enumerations such as Direction (xDir, yDir and zDir) and OutputFormat.