Maximum number of wires allowed for junction box
I think the most likely interpretation of the labeling would indicate since the NEC only requires the box fill calculation to count the ground once then you could have two 12/2, three 14/2, or two 14/3, but it could be argued that only one 12/2 or two 14/2 would be allowed.
The Code in section 314 specifies the volume (cm³ or in³) required per wire based on size of wire, and has a couple of details like counting certain types of fittings, only counting the largest ground once, not counting wires that start and end in the box. The confusing part is the Code also says installations shall comply with the UL (or other lab) Listing which includes the instructions supplied with products.
Normally the Listing is more restrictive, so following the Listing doesn't conflict with Code, but often light housing boxes like yours allow more fill than Code. I have always found Inspectors allow the Listing to overrule the Code. If an Inspector told me I would have to comply with both, meaning the tighter more restrictive standard I would have a hard time arguing against that, but I never have had to. Normally I do try to comply with the Code restrictions also to avoid arguments.
The size on the box is also relevant if using some combination of NM/AC/MC cable with smaller fixture whips.