Browser script hack to extract slack emoji via the JS console.

hack-extract-slack-emoji-via-browser-script.js

var emojis = {};
var $timer = setInterval(captureEmojis, 50);

function captureEmojis() {
  document.querySelectorAll(".p-customize_emoji_list__image").forEach((el) => {
    emojis[el.alt] = el.src;
  });
}

function stopCapture() {
  clearInterval($timer);
  console.log(emojis);
}