The Extreme Long Shot (ELS) or the Wide Shot (WS) is where a character is very far away; further than the LS.
The prime focus of the ELS is on the environment the character is in. Often used to show sweeping landscapes, buildings, characters with crowds, etc.
The use of Extreme Long Shots is important in establishing the setting of a film, ie, the world in which the characters inhabit. Because the characters are so small on screen, they do not convey much directly about the character, but when used in conjunction with Close Ups/Mid Shots that convey a character's reaction to the setting, are highly effective at building a believable world.
Opening shot of the film, a birds eye view (High Angle) of a suburban neighborhood. Familiar, normal.
Arguably, this is a Long Shot, but also falls under 'establishing' the setting. A suburban home, familiar to us as being a 'normal' setting, which helps us understand the characters and connect with them.
This ELS shows Bree taking the cookie jar to be smashed. The shot helps communicate that she is far from home, and is isolated. This builds tension, and makes her action in smashing the jar a brave mood that dissipates the tension.