In principle that what [Expand all comments script][expand] does, but with two major differences:

[expand]: https://stackapps.com/q/7993/29193

* Scrolls the page back to the initial target of the corresponding link you selected (i.e. to question, question comment, answer or answer comment) after comment expansion (since also "clicking" on a link programmatically – [_show **n** more comments_][#] in this case – scrolls the page to that link).
* [internal] Uses regex for `@include` and `@exclude`. (Agreed, this prevents the really nice _Sites_ favicons in Tampermonkey's _Installed userscripts_ tab.)

[#]: http://example.com/#

```` lang-js
// ==UserScript==
// @name        StackExchange – Expand Hidden Comments
// @description Expands hidden comments of SE questions and answers on sites with the new naming convention <something>.stackexchange.com and on Ask Ubuntu, Code Review, Server Fault, Super User and MathOverflow (the script is easily adaptable for more).
// @version     19.12.1
// @icon        https://upload.wikimedia.org/wikipedia/commons/5/5a/Icons-mini-comment_yellow.gif
// @author      Gerold 'Geri' Broser <https://stackoverflow.com/users/1744774>
// @license     GNU GPLv3 <http://www.gnu.org/licenses/gpl-3.0.html>
// @homepage    https://stackapps.com/questions/8514
// @supportURL  https://stackapps.com/questions/8514
// ------------
@include /^https:\/\/(\w*\.+)?(stack|ask|code|server|super|math)\w*\.(com|net)\/questions\/?.*$/
// Matches:             |<none> ||      ⬑– Domains that don't follow |  | TLDs  || Paths        |
//                      |meta.  ||      the <something>.stackexchange|           | + possible   |
//                      |       ||      scheme...                    |           |   fragment   |
//                      |⬑–––––––⬑–––– ...and those that do.        |

// @exclude /^https:\/\/(\w*\.+)?(stack|ask|code|server|super|math)\w*\.(com|net)\/questions\/ask\/?.*$/
// Matches:             |<none> ||      ⬑– Domains that don't follow |  | TLDs  || Path              |
//                      |meta.  ||      the <something>.stackexchange|           |+ possible fragment|
//                      |       ||      scheme...                    |
//                      |⬑–––––––⬑–––– ...and those that do.        |
//              ---- extend bracket expression(s) above for new site(s) ----
// @namespace   igb
// @grant       none
// ==/UserScript==

(function() {
  'use strict'

  try {
	console.log("BEGIN StackExchange – Expand Hidden Comments...");

	// Get top first element in viewport to scroll to it after expansion, such restoring the viewport view.
	// The top first element can be one of the following:
	//   - a question (i.e. top of the page)
	//   - a question comment --+
	//   - an answer            +--> opened via a corresponding link
	//   - an answer cpmment  --+

	let topFirst = void(0)

	// Is question top first?
	const search = document.getElementById('search')
	topFirst = search.getBoundingClientRect().top > 0 ? search.parentNode : void(0)
	//console.debug("Is question top first?...", topFirst === void(0) ? "No" : "Yes")

	if ( topFirst === void(0) )	{
	  // Is question comment top first?
	  let questionComment = void(0)
	  for ( questionComment of document.querySelectorAll('div#question div.comment-text') ) {
		//console.debug(questionComment, questionComment.getBoundingClientRect().top)
		if ( questionComment.getBoundingClientRect().top > 0 ) {
		  topFirst = questionComment
		  break
		} // if
	  } // for
	  //console.debug("Is question comment top first?...", topFirst === void(0) ? "No" : "Yes")
	} // if

	let answer = void(0)
	if ( topFirst === void(0) ) {
	  // Is answer top first?
	  for ( answer of document.getElementsByClassName('answercell') ) {
		//console.debug("answer:", answer, answer.getBoundingClientRect().top)
		if ( answer.getBoundingClientRect().top > 0 ) {
		  topFirst = answer
		  break
		}
		else {
		  // Is answer comment top first?
		  let answerComment = void(0)
		  for ( answerComment of document.querySelectorAll('div#answers div.comment-text') ) {
			//console.debug("answerComment:", answerComment, answerComment.getBoundingClientRect().top)
			if ( answerComment.getBoundingClientRect().top > 0 ) {
			  topFirst = answerComment
			  break
			} // if
		  } // for ( answer comments )
		  //console.debug("Is answer comment top first?...", topFirst === void(0) ? "No" : "Yes")
		  if ( topFirst !== void(0) )
			break
		} // if
	  } // for ( answers )
	  //console.debug("Is answer top first?...", topFirst === answer ? "Yes" : "No")
	} //  if

	[...document.getElementsByClassName('js-show-link')].forEach( link => {
	  link.click() // scrolls page till last clicked link, therefore view is saved above and restored below
	})

	setTimeout( () => {
	  console.log('BEGIN StackExchange – Expand Hidden Comments...delayed...')
	  // Restore viewport view
	  topFirst.scrollIntoView(true)
	  //console.debug(topFirst, topFirst.getBoundingClientRect().top)
	  console.log("END StackExchange – Expand Hidden Comments...delayed.")
	}, 1000 ) // increase if time isn't enough to scroll view to initial position
	console.log("END StackExchange – Expand Hidden Comments.")
  }
  catch (e) {
	console.error(e)
  }
})();
````

### (Possible) TODO ###

* Use jQuery to become browser agnostic if according issues arise.

<br />
Hints for improvement are welcome!