HTML Page Redirection

What should a reader see when they open a bookmark to a page that has moved? The recipe site has just reorganized its addresses. The lemon cake recipe used to live at https://example.com/lemon-cake.html, and now it lives at https://example.com/recipes/lemon-cake. Old bookmarks, old links on other sites and old search results all still point to the first address.

The answer is a redirect: when the browser asks for the old address, it is sent on to the new one automatically. There are two ways to do this, and they work at different stages of loading a page.