timezone.js calls the system.timezone route with a date parameter that is never used

I am removing the Novice tag from this issue because I think the resolution is ambiguous with the does not break anything comment.

I’m using this documentation as a source: https://www.drupal.org/community/contributor-guide/task/triage-novice-is...

do we know if a contrib module could be using this?

Lets see what committers think.

This needs git archaeology before it can be committed - we need to know whether this was never used, whether it should be used, whether it recently became unused because of other changes etc.

The dateString argument has been sent since:

commit b4435decef6ebbfa2c5e9da23c2916fca3b04f57
Author: Angie Byron <webchick@24967.no-reply.drupal.org>
Date:   Fri Nov 21 04:33:28 2008 +0000

    #11077 follow-up: adding missing timezone.js file.

The original menu callback was this:

 
 /**
+ * Menu callback; Retrieve a JSON object containing a suggested time zone name.
+ */
+function system_timezone($abbreviation = '', $offset = -1, $is_daylight_saving_time = NULL) {
+  // An abbreviation of "0" passed in the callback arguments should be
+  // interpreted as the empty string.
+  $abbreviation = $abbreviation ? $abbreviation : '';
+  $timezone = timezone_name_from_abbr($abbreviation, intval($offset), $is_daylight_saving_time);
+  drupal_json($timezone);
+}
+

So this was added in 2008 with the original issue, and has never been used.

But also - I think we should open a follow-up to look into removing the route and AJAX request, if it's only a fallback for non-compliant browsers, then we should be able to fall back to the user selecting their own timezone.