What does the 'Accept-Encoding' checkbox do ?

[JeanMenage]

Hi, i've noticed that on different site, depending on if this checkbox is checked or not the website will act differently, but when i look up at the headers sent, nothing change, that's what leads to my question. Thanks !
ex with 'accept-encoding' checked:

Calling URL: https://google.com
Sent Headers:
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/80.0.3987.149 Safari/537.36
Pragma: no-cache
Accept: */*
Content-Type: application/x-www-form-urlencoded
Sent Cookies:

Address: https://www.google.com/
Response code: 200 (OK)

without:

Calling URL: https://google.com
Sent Headers:
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/80.0.3987.149 Safari/537.36
Pragma: no-cache
Accept: */*
Content-Type: application/x-www-form-urlencoded
Sent Cookies:

Address: https://www.google.com/
Response code: 200 (OK)

I can't see any differencies

[Fairy]

try to look at the post data that's sent