An extra legroom is a place with extra legroom. Most often, such places are located in the emergency rows or the first rows of a given service class. Some airlines have introduced the possibility of paid booking of such a place. Others allow a free seat selection. If this place is located at an emergency exit, the passenger must meet certain safety requirements, including be of the appropriate age, have no health problems, or be able to use English or any other language indicated by the line. Each line specifies exactly who can occupy such places. If a passenger buys such a seat and it turns out that he has a broken leg or is pregnant, the staff at Checkin or Gate is obliged to replace such a seat with a standard one. Remember that in the event of an emergency landing, you will be responsible for helping with the evacuation ;)