It looks weird, but consider it a table with 3 rows, and 10 columns. The first 4 columns are actually used, in order, by Air, Argon, Krypton, Xenon.
It actually looks better in the original Fortran code (see here)
If you want to track down what's happening, HeatBalanceManager.cc (check out a few lines later) and WindowManager.cc are the two others files where you need to look.
You probably want to check out the entire Window Heat Balance section of the documentation (online here)
Can anyone tell me where I can see the properties of Air, Argon or other inert gases that Energy Plus use when we select them in "WindowMaterial:Gas" for using them in glazing systems?