i don't think you'd need to hack the internals, you just hook into that event to do what you need:

  htmx.on("htmx:configRequest", function(evt) {
     evt.detail.parameters['my-html'] = evt.target.outerHTML;  // or whatever
  }

you can jump on the discord and we can help you out when the time comes:

https://htmx.org/discord