With a windowed watchdog timer, there is a minimum time as well as a maximum time. A normal WDT only has a maximum time.
The timer is reset when the watchdog timer reset command is executed. This is the same as a normal WDT
If the timer gets to the maximum time, the processor is reset. This is also the same as a normal WDT
If a second watchdog timer reset command is executed before the minimum time, the processor is reset. That is not the same as with a normal WDT.