Confused about geom_uzip

I have an geom_uzip image and what I'm confused about is the following. The first few lines of the image file are as follows:

#V2.0 Format
(kldstat -m $m 2>&-||kldload $m)>&-&&mount_cd9660 /dev/`mdconfig -af $0`.uzip $1
exit $?

But when I try to execute them manually they simply don't work on the mount part as the memory drive with extension .uzip doesn't exist. For example executing mdconfig -af root.img generates /dev/md0, but the the top of the image loads the file_name.uzip. How is that happening ?

Also, I've been looking around for ways of testing the geom_uzip images and can't really find anything online. Does anyone know of any?
The script is for mounting CD/DVD images (mount_cd9660(8)). Possible but that would mean the image is a compressed CD image. If the image is actually a geom_uzip(4) image the corresponding md0.uzip will get created automatically.

Data written in the GEOM label area allows
     geom_uzip to detect compressed images which have been created with
     mkuzip(8) and presented to the kernel as a logical disk device via md(4).
     geom_uzip creates a unique md#.uzip device for each image.

This leads me to believe the image you have is not a geom_uzip(4) image.
Let me ask you this. Isn't the snippet added automatically by mkuzip to an img file ? Wouldn't that alone indicate that it is an geom_uzip img? I'm just trying to figure out if wasn't geom_uzip then why would the head be like that? Anything you can think of ?