Combining L and R impulse responses into a stereo impulse

Hi All , Been using the REVerence and checking out all the .Wav’s on the web some are amazing .

Seem odd the are mostly .L .R files , I haven’t used impulse response reverbs much and was wondering why there not Stereo wavs ?

and what is going on inside the REVerence if you load a .L but have stereo out from the REVerence