The technique starts about 19 minutes into the video for those of you want to get right to it.
As the title describes this is a very specific workflow to bring in the solved matchmove data from the excellent matchmove tools in Blender. The reason for doing this is although Fusion has a great camera tracker, it did not implement a dedicated manual supervised tracker. This workflow is developed to utilize the powerful tracking features of Blender and then importing them into Fusion to use it's powerful node compositing features.