Understanding Head Tracking 21

[fatbringer]

https://motchallenge.net/data/Head_Tracking_21/

Hello, i have a question regarding the annotations file for the HT21 dataset.

Under train, we have a gt.txt and det.txt

for train's gt.txt, we have something that looks like

1,46,1694.34,839.09,36.99000000000001,41.25999999999999,1,1,1.0
1,47,984.11,609.0,25.860000000000014,29.5,1,1,1.0
1,48,1189.35,611.69,26.410000000000082,30.25,1,1,1.0
1,49,422.46,791.74,34.01000000000005,37.01999999999998,1,1,1.0
1,50,1069.16,442.35,16.919999999999845,18.299999999999955,1,2,1.0
1,51,1240.72,590.78,28.049999999999955,31.779999999999973,1,2,1.0
1,52,1059.79,611.3,26.559999999999945,33.33000000000004,1,1,1.0
1,53,1265.0,443.0,14.0,17.0,1,1,1.0

and for train's det.txt, we have something that looks like

1,-1,785.64667,694.59534,29.265869140625,32.0731201171875,98.06506037712097,1,1,1
1,-1,1060.6016,611.3489,25.35693359375,28.917236328125,95.28763890266418,1,1,1
1,-1,1026.9801,571.764,25.02392578125,26.618896484375,95.08466720581055,1,1,1
1,-1,1688.9934,672.945,28.603759765625,28.971923828125,95.08053064346313,1,1,1
1,-1,1189.4504,611.845,26.663818359375,27.52783203125,94.82117891311646,1,1,1

under test, we only have a det.txt , which looks like

1,-1,1106.2294,511.94147,32.61083984375,33.6319580078125,95.72254419326782,1,1,1
1,-1,1185.3074,653.7112,35.015869140625,34.65234375,95.30508518218994,1,1,1
1,-1,974.9225,628.08685,33.3131103515625,35.593505859375,94.69307065010071,1,1,1
1,-1,1726.2141,508.69736,31.886962890625,33.702545166015625,91.82578921318054,1,1,1
1,-1,1782.3907,678.19464,36.035400390625,37.4072265625,91.17299914360046,1,1,1
1,-1,648.1375,505.2013,30.217041015625,30.18896484375,89.74709510803223,1,1,1
1,-1,1589.8481,504.23087,34.19921875,33.922637939453125,89.40604329109192,1,1,1
1,-1,1031.0326,626.85864,31.246337890625,32.0919189453125,88.16178441047668,1,1,1

My questions:

1. What do these numbers mean? They clearly do not fit into the usual MOT dataset annotation format of 10 values containing
   frame, id, bb_left, bb_top, bb_width, bb_height, conf, x, y, z

2. Where might we find gt.txt for test folder?
   An extension, why is there no gt.txt?