It's probably the author's vision. Thus far, all we know is that the CAS said that the PAF's interested in a twin-engine design with supercruise and room for directed energy weapons. Moreover, it has to be ITAR free (i.e. 100% free of any controlled US components/subsystems). The PAF is open to partnerships, so it's keeping an eye on the TF-X, but I imagine the FC-31 and/or a new Chengdu project are also under consideration.
@JamD the confusing thing about Azm is that "next-gen" doesn't have to be confined to an FGFA program. You can, in theory anyways, continue working on the JF-17 as-is and evolve its design. Even HAL is doing as much with their Tejas Mk2. Likewise, one of South Korea's KFX proposals was basically an up-worked T-50.
I wonder, at some point, if the PAF basically opted to bifurcate the JF-17 and FGFA into separate streams. So rather than the FGFA replacing the JF-17, the JF-17 line continues along an evolutionary track of some kind. That may also reconcile some of
@messiach earlier points re: Azm being a natural next step from JF-17 (as well as the previous CAS' statements about Azm's design being done with Chinese help, etc).
Heck, if we take this to one natural conclusion, the twin-engine FGFA might just end up being more of an import or consortium project, while Azm = JF-17 NG.