After installing this script you will be able to meet homeless people, who will publicly go to the toilet, walk on the street drunk, or just sit on the ground and scratch their privates.
Such behavior of pedestrians was planned by the developers, but was not included into the final version of the game. You can read more about it in the video from Vadim M.
And this script fully restores that possibility. Homeless people will appear among normal pedestrians every few minutes.