The only thing I know so far is that this rifle was based on the German G36, the original plan of the Mexican army was to built the G36 with the license of HK, however somehow they didn't get to a deal, therefore the Mexican engineers had to create the Mexican version with the same machinery the G36 is built with.
There is no official technical data available at the moment, some sources say its caliber is 5.56. And it doesn't have carry handle at all. It also doesn't have an optic scope, instead, it has iron sights. Anyway this is not official, so lets not believe everything.
Edit on that: It seems, that finally the license plan worked out. So the Mexican rifle is build under License of HK.