Dev in question do not pretend to implement whole OpenGL 3.1 core profile.

But to treat it as a goal IF hardware support it (and if mesa support GLSL 1.40 :P ).

On the github is STATUS file go and read it.

On the other hand OpenGL 2.1 =\= OpenGL ES, so there is no guarantee that there would be full OpenGL 2.1 on PS3 either.