No indication unless you interrupt several in succession then you get a message to keep driving for 20 minutes or something similar. If you interrupt one it’s ok but then be sure you are driving for 30 minutes or so next startup. I wish they had an indicator. My ODB2 software has PID’s but I have yet to find a regen one.
I have noticed my regen has two ways it does it: the periodic that will go for about 15 to 30 minutes and what I call the extended. The periodic comes on every couple of weeks or so. On the extended I get a light on the dash that looks like a diagram of air blowing through a filter. Under the extended it may go for several hours or during several days depending on my driving habit.
Every time after I visit the dealer the light will come on, just as I pull into my driveway. They say they don't do anything but it only happens after a dealer visit and they plug their scanner in. Normal Regen on my van happens about every 300 miles city and about 600 miles at 65 mph going faster than 65 is a longer distance between regens from what I have seen, your mileage may very.
OBD fusion has a dpf capacity % when capacity reaches 75% regen should start, as I stated should and not will. When regen is done the % will go back to single digit. On the highway I have seen the capacity over 85% without a regen from reading the 3 dpf exhaust temp sensors and then back to zero for a fresh start.