What color space to use for EXR in textures I've searched high and low for this, and cannot find an answer anywhere, even in the new 2.80 docs. 

When you import import or environment textures in 2.80, the new texture node has several colour space options: 


xyz
sRGB
Raw 
Non-color
Linear ACES
Linear
Filmic Log


What do they do, and what one SHOULD be used for EXR files? 

Thanks
For EXR use Linear. 

(If you know that your EXRs are encoded using other color space... then you would know the answer already)