Let's analyze the functions of common browser buttons.
(A) Closing the current tab is usually done by clicking an 'x' on the tab itself.
(B) Opening a new tab is done by clicking a '+' icon or using a keyboard shortcut (Ctrl+T).
(C) Returning to the previous web page is the function of the 'Back' button (usually a left-pointing arrow).
(D) The refresh or reload button (usually a circular arrow) instructs the browser to download the current web page again from the server. This is useful if the page did not load correctly or to see the latest updated content.
Therefore, the purpose of the refresh/reload button is to reload the current web page.