TAS Explained: Super Mario Bros. 3 in 0.2 seconds

TAS stands for tool assisted speedrun.

TAS is cool as people can use it to find the most optimal way to finish a game. Sometimes tricks are too hard for people to do or at least they are believed to be to hard for people to do. Sometimes TAS “only” tricks end up being done by people.

With tool assistance?

How do you cheat in tool assisted speedruns? Using a romhack?