The Home and End buttons typically take you to the beginning of the line, or the end of the line respectively.
Firefox browser does not support this in the URL field. Home and End will do nothing in the URL field of Firefox.
In Safari, the Home and End button will navigate to the beginning of the webpage and to the end of the webpage even while the cursor is located in the URL field.
These are issues with the browser on the MAC OS platform that unfortunately must be resolved by the software vendor.