It was a Bastion 3-D printed titanium bar that snapped. It's painted to match the bikes. It was reported awhile ago that Australia had partnered with Bastion to custom build several components, and there's a video going around some other social media sites showing Bastion making the bars.
And yes, the new super Argon that the Aussies are on has two different forks - a narrow one and a normal width for sprinting. The new ones are only thru-axle compatible, and TA compatible track wheels are pretty much non-existent beyond national teams. I'm guessing some of the teams may have traditional forks ends to run their normal wheels. I say this having seen a pic of Kelsey Mitchell warming up on what appeared to be a new Super Argon frame but with what looked like an older IO, though it was not a perfect pic for identifying gear.