This Gunpla is based on a fictional anime series that bridges the gap between Gundam F91 and Crossbone Gundam.
It's an original design.
As you can probably guess from the name, this Gunpla is based on the final battle specifications of Gundam F91.
I've experienced this firsthand when trying to use the F91 as a base model in Gundam Breaker, but the original design is so perfect that the more you modify it, the worse it becomes!

Gundam F91 Full Formula... and an attempt at a personal completion of the F91. | アルジドノ's Gunpla works