I’m probably going to the_dunk_tank for this, but…

Requirements: Violentmonkey browser extension. Tampermonkey and Greasemonkey might work as well, but I haven’t & won’t test them. Note also that I haven’t & won’t test Chrome or Edge, either.

// ==UserScript==
// @name        lemmy-delete-tagline
// @match       https://hexbear.net/
// @require https://cdn.jsdelivr.net/npm/@violentmonkey/dom@2
// ==/UserScript==
VM.observe(document.body, () => {
  const node = document.querySelector('#tagline');
  if (node) {
    node.remove();
    return true;
  }
});

Edit to add: Maybe it needs some work: when I click on the homepage icon from another page, it fails to remove the tagline. I’m an old who doesn’t understand how progressive web applications work. Maybe I need to remove the return true and also tune how often the observer observes. Or maybe there’s some trigger I should hook it up to. Simply removing return true does seem to work, but I have no idea if it’s at the cost of any appreciable performance.

Edit to add more: !companero@hexbear.net suggested that I just use a uBlock Origin filter. I tried it and it works. It’s as simple as:

hexbear.net###tagline