Every airline uses some sort of a contractor or a shared piece of software for online checkins. You can tell by the formed URI fragments and the JSON being sent back and forth.
Its all trash. I wanted to work on a business that unified all check-ins under single company. I do not think however, it is reasonable given that all of these airlines have the process, as shit as it is, for a reason.
They isn't much in common across airlines as far as the actual code goes, though. Beyond that they all use some limited set of CRS providers, like Galileo, Sabre, Amadeus, etc. That is to say, there's some common code, but it's pretty far down the stack, and only common across a few carriers.
One example: https://www.nytimes.com/2017/09/28/business/airport-check-in...
Hit several carriers, but not all by a long stretch.
Unfortunately, not just Emirates, but a huge number of e-commerce companies across industries like travel, shopping, healthcare are subjected to similar leaks.
You are probably refering to GDS - that’s been up since 1960’s: https://en.m.wikipedia.org/wiki/Computer_reservation_system#...