Welcome to one month ago!
And to F1T as well.
You can read about this development in the thread dedicated to the Merc MGP01. By looking at the date of the development article you can go back to it in the MGP01 thread to see what was being talked about then, and coincidentally you can find the airbox as a main topic. Here is where it all starts at about one month ago: viewtopic.php?f=12&t=7904&start=1305
And if you take a look at right hand side of the article that you posted, there's a yellow box that says "Discuss this in the forum", which will lead you to the thread I have given you above.