It's an Airbus jet, you donkey.
It's an Airbus A321neo. Few easy ways to tell: A) Delta runs a near totally Airbus fleet, they have a few old Boeing planes left. B) The winglets, only Airbus planes have have that curved style.
And to top it all off, it's a fire that started possibly because of some faulty wiring with the skyway electrical connector being plugged into the plane.
So again.. you donkey.
The 737 also has the curved tips, and Delta has plenty of Boeing aircraft. It's actually really hard to tell them apart for a layman (the tail and nose are slightly different ?).
But you're right - it seems like it's irrelevant, as the culprit seems to be a ground-based generator.
Boeing's winglets are a little more angular, Airbus planes have a more elegant sweep to them. But yes, perhaps not the easiest thing to spot.