….as per the low fuel checklist
Assuming, of course, that they had a "Low Fuel" EICAS message. Not having the statutory and/or company fuel policy volume onboard doesn't necessarily mean the tanks are low. If, as has been suggested earlier, they no longer had a
suitable alternate airport and the company policy requires it, they may have had plenty in the tanks, just not enough to go anywhere
suitable, other than Sydney.
Having declared a Mayday I would assume an ASIR has been submitted and thus the details
should be known somewhere down the track.