Philip Taylor writes:
 > >>   L:  works under LaTeX
 > >>   OL: works under LaTeX 2.09
 > >>   P:  works under plain TeX
 > >>   X:  support application, OS specific
 >
 > +:=  E1: requires e-TeX V1
 >      E2: requires e-TeX V2
 >      On: requires Omega Vn...

shall we just let the authors provide this clue? rather than trying to
test it independently?

sebastian