can someone explain the design of this shoe sole?

[random512]

Can someone explain the design of this shoe sole? I bought some Rendenbach leather soles from leatherandgrindery.com. I received them and they look like this:

https://www.dropbox.com/s/mz1nky4k724v7j3/IMG_20180420_211855__01.jpg?dl=0

Does the cobbler essentially inset this leather piece into other leather pieces to form a full sole? Does this particular style of leather sole have a name like "forefoot sole" or something like that?

It seems like insetting this type of component into a sole would have more potential points of failure than using a solid full leather sole. This is my first experience ordering leather soles so I'm trying to figure this out.

 

[bengal-stripe]

This is a 'half sole' for repairs.

The old, worn sole is removed but only under the foot, not in the waist (the 'waist' is the section where the sole lifts off the ground to disappear under the heel). The replacement sole is used at full thickness under the foot but thinned down in the waist where you have two layers (old and new sole) overlapping.

If you do not want the soles overlapping and have the replacement sole going all the way back under the heel, you need a 'long sole' and have to remove and reattach the heel-block again. So it is more work and will be more costly for the repair.