Looking at different tires from Trek, they have names like T2, R3, AW1, but I can't find anywhere that decodes these names and tells me the difference between one or the other.
They are indicators of what product line Trek is placing each tire in. For example, R=road, AW=all weather, t=Touring, XR=cross road (or something like that, indicating smaller tread that is not too big for mixed road riding) G=gravel and so on. I would say that these prefixes don't really mean much, just choose a tire that is appropriate for the type of riding you will be doing.
I don't want to add links, since they will become broken eventually, but look at the Trek bicycle web site. (they own Bontrager) If you look through the tire section of the site, then filter for eg. road tires, and click on a specific tire, you'll see some specs on the tire, eg tpi, the weight etc