Once thing that Auron discovered upon his return to Zanarkand was that people always wanted to know how he survived the Final Battle. [Spoilers through Zanarkand, especially for Braska's Final Summ...
People ask how he survived and why Jecht didn't. People ask what he remembers.
(Braska, face white and body shaking, staff stuck into the ground as though to anchor him. Auron hadn't watched - he'd hacked mechanically through Sinspawn until he heard Braska yelling - actually yelling - "Stalling won't stop us now Jecht!"
The blast of air threw him aside like a discarded weapon.
After that there's only -
Jecht, changed and not - a sight that almost stops his heart. It would have been easier if he'd been unrecognisable, if Auron couldn't look at the mark on his chest, the scars in the aeon's arms, the aeon's face, and think Jecht -
The tracing of the Final Aeon's sigil beneath Braska's feet, a barrier that burned through any Sinspawn foolish enough to get close, keeping both them and Auron away -
Jecht spiralling out of the sun towards Sin, clawed hands spread, shrieking like a fiend triumphant -
Braska falling, staff shattering as his hands left it, the pyreflies already starting to flow from him as Jecht reaches into Sin and rips out something black and moving -
Braska falling, hand close enough to touch -
Jecht screaming, Sin's heart - what else could it be? - sending black tendrils up Jecht's arm, Sin's final trick -
Jecht dropping down past the cliff edge, pyreflies streaming in his wake -
Braska falling, a smile on his face and the words "We did it" on his lips - )
And Auron always says nothing.
If they were so curious, then Yunalesca was still - despite his efforts - waiting in Zanarkand to enlighten then.
She wouldn't be there for much longer.