During PRINT_START macro:
Just started actually printing:
10% done:
25% done:
Actual finish time:
You can see print progress even during the PRINT_START macro, and see how stable and accurate the ETA is (depends on how consistently your slicer estimates the print time)
Records how long each stage of the PRINT_START macro takes to get an estimation, and records how the slicer estimation over or undershoots, and compensates based on historical data and live print stats.