There’s a fun way around that specific “remove sticky” bookmarklet, because it only looks at elements within the body. But did you know: you can actually show content from the head! For example, you could display the document title and make it sticky:

  head, title {
    display: block;
    position: sticky;
    top: 0;
    left: 0;
    right: 0;
  }

An example of using this technique (minus stickyness) in real life (for some loose value of “real life”): https://github.com/martenbjork/github-xp/issues/13

You can apply this technique to <script> and <style> content as well to get other text nodes that are normally hidden to appear on-screen. You could also use ::before and ::after psuedoelements on other elements (and for bonus marks remember you can use attr() within their content). But no regular formatting within the head. Well, unless you append the nodes to the head with JavaScript. Yeah, the DOM lets you create nominally illegal structures that can’t be serialised again.