it appears that having a mask is not optional but a requirement in 0.2.2, because tracking process won't start without one. When clicking the track button the blender console will simply say:
Running inference on: [LogicalDevice(name='/device:CPU:0', device_type='CPU'), LogicalDevice(name='/device:GPU:0', device_type='GPU')]
INFO: Initialised darknet network found!
'bpy_prop_collection[key]: key "Mask" not found'
No mask found!
At step 5 ("Masking regions of interest (OPTIONAL)") at: https://github.com/FabianPlum/OmniTrax/blob/main/docs/tutorial-tracking.md
it appears that having a mask is not optional but a requirement in 0.2.2, because tracking process won't start without one. When clicking the track button the blender console will simply say:
And then it stops.