HoMM3 HD is a mod (add-on) for the game Heroes of Might and Magic 3.

It's unclear why people are so insistent on having the time count down only after a turn is completed. If you're playing, just play! If you're busy with other things or trying to keep up with your opponent's turn, then don't play Heroes. Why should your opponent have to wait for you, and without any warning? If you're distracted, just send a quick message in the chat and ask them to wait or save the game – it takes only a few seconds and is a basic act of sportsmanship.
This method of turn timing ruins the chess timer!