This is an old revision of the document!
This is for the V1 only
The “set screw” or “grub screw” that holds the heatbreak and Bowden tube connectors is M3-0.5 x 5mm (6mm will probably work) and takes a 1.5mm Allen wrench or 1/16“ Allen wrench.
Amazon.com - Set Screw, M3 x 5mm (10)
HomeDepot.com - M3-0.5 x 5 mm Alloy Metric Socket Set Screw (2-Pack)