There are plenty available!!!
Here, this is the bag in question:
Here's how they did the strap:
Not only did they cut a single strap and folded it and stitched it, but they actually put it together from two three shorter straps. Waste not, I guess.
Contrary to my remembrances above, the glue didn't really go all the way to the centre or the edges—guess they only glued the area round the fold:
At some point a wayward cut happened, maybe an accident? Still, waste not, just stitch it in place and carry on: