Per your request, here's a photo of a typical front bag.
It is a little hard to see because it is black. I'll try to illuminate it with words.
This bag is about 15" X 15" when laid flat like you see it. That's a yardstick laying on the floor above it. The top two 1/2 inch wide webbings have 5/8" quick release buckles about midway up on them. The buckles attach to the top bar of the pack frame.
The 5/8 inch quick release buckles on the lower part of the bag receive webbings from the lower corners of the pack frame. I put 3x5 cards under them so they are more visible. The 3x5 cards are not part of the front bag.
The top webs are much longer than they need to be for a couple of reasons. I use them to rest my arms while hiking and they connect to the bottom buckles to turn the front bag into a day pack.
If you look closely you will see a cordlock that is attached to the drawstring closure of the bag.
In this photo you are looking at the side of the bag that goes against my chest.