Nice bike! Some googling will get you more info, and there are extensive Trek US catalog scans online, not sure about Euro catalogs.

The 790 was Trek's highest-end steel hybrid/trekking bike, maybe only in the catalog for a few years. US-built in the newer Whitewater factory IIRC. Hybrids grew as a category and were spec'd upscale in the mid-'90s, targeted at folks who wanted a bike with wider tires and more upright riding position (like an ATB), but weren't riding off-road. They didn't need/want the robust build of an ATB, but road bikes at the time were primarily narrow-tire, aero-position road racing designs. The 520 was still in Trek's line, as a touring road bike, targeted at a different rider. The hybrids had wider tire clearances IIRC, and were normally spec'd with wider/knobbier tires than the 520.

Trek had to spec their trekking bikes with fenders, racks & lights to get market share in the Euro market, so your 790 looks to be stock Euro spec. US-spec 790 had no racks, fenders or lights. The Euro bikes also had to be very close to fully-assembled for Euro dealers, so Trek spent a lot of time/money increasing build % at the factory. Had to get Giant onboard as well for the outsourced bikes. Later Trek bought some factories in Europe, and did assembly on-continent.

There weren't a lot of steel hybrid frames sold in the US, those in the know look out for them because they can make nice drop-bar builds. Trekking was a very large share of Trek's Euro business, so they may be more common over there.