The correct tension is maintained by the Idler that the bottom of the belt rides up on after coming off the drive ring. The dropout that holds the axle and wheel, is integrated in once piece with a hollow plate, held in place by two bolts and nuts. The nuts are on the inside and held by a narrow track so no wrench needed. The bolt heads can be seen in the above photo, countersunk into the short, angled, vertical section of the swing arm just forward of the hub. The angled, vertical piece backed up to the forward edge of the short swing arm section is part of the dropout/bracket.
I have over 4,000 miles on my Homage, with no need to adjust the belt tension. It appears to not have stretched at all since new.
I have had the wheel off numerous times (without letting any air out). The wheel comes down, out of the drop outs and held even with, and immediately below the bottom of the dropout slot. Grab the belt at the back end of the rear sprocket and let the axle/wheel come forward about 3/4" and the belt can peel off. It took several attempts to figure this one out, doing the deflation thing the first time.