It means that all Tracks/Patterns won’t reset at the same time at the end of a 'Master" cycle.
If you had Master setting of 32 with 4 Tracks running thus
- 15 steps
- 12
- 7
- 6
Then on Master step 32
- would be on its own step 2
- would be 8
3…4
4…2
Master will now reset all 4 tracks back step 1.
A setting of INF would allow them all to carry on on their own merry way.
Track 1 would reach step 3, Track 2 step 9 & so on.