A bit unfortunate choice of the name since there is another CIL too: https://ecma-international.org/publications-and-standards/st...
(I first learned about CIL in https://people.eecs.berkeley.edu/~necula/Papers/cil_cc02.pdf)
I guess ECMA should have done better research.
2012 is just the latest version. It was first published in 2001, and started in 2000. They're so close together that it's difficult to say if one would have been able to find the other.
https://en.wikipedia.org/wiki/Common_Language_Infrastructure
And even the fact that this is a fork of an earlier project and the name comes from that doesn't stop it!
(I'm aware I have chosen a very weird thing to be getting annoyed at over my breakfast crumpets this morning)