What is the h parameter when loading css ?

Question

I'm using Bootstrap studio and i got this parameter "h" when loading js and css, can somebody tell me what it is ?
"/my_assets/sheet.css?h=9af5f655239f5ce4fa692ca1c1513d50"
When i remove that parameter from css it loads without a problem but when i remove it from js it doesn't load

Answer 1

Kostas Šliažas thanks for the answer , i disabled the "version assets" option and it worked :)

Answer 2

Kostas Šliažas i kept searching like that and never found anything then i opened the code and there was nothing about validation