Chuck its basically a high altitude funny runway rating.
Its got nothing to do with flying around mountains you can do that you just can't land at these airports without special training.
They are steep gradient unidirectional runways with a flat area at the top that acts an apron.
As for the none EASA ticket they really won't care, they don't particularly want none locals flying in their anyway. And I suspect once things shake themselves out they will change the rules so that a mountain rating will not just be required and you will need some sort of local sign off before you can use them. And it will go back to the old altiport rules anyway. The airports still retain the right to set their own requirements for approval to use them. And that will include a French check out. And I wouldn't be surprised if they don't impose a French language requirement which is virtually impossible to get unless you hold a French license for EASA licenses outside France.