Back on a Mac --- What re the new units of time?

Hi, I’ve been using NTrack on a Windows NT (yeah!) machine for about 15 years, and just upgraded for the first time in about 10 years – and now on MacOS Catalina. I love most of the many changes since those Dark Ages, but I am mystified by the units in the time counter. They show as X:Y:ZZZ where X seems to count in approximately 2-second intervals, Y counts from 1-4, and ZZZ counts from 1-959. So, seconds seem to be broken up into about 1920 units.
Any idea what these units really are?

Many thanks,

Dave

OK; it’s all in the manual – but to find it you have to know to search for M:B:T, which represent measures, beats, and ticks – set by default to 4 beats/measure and 120 ticks/beat. You can get back to seconds and frames for the displays by going to the Preferences > Appearance menu.

Dave