TYPO3 Core

Steps to reproduce:

1. Log in to the BE.
2. enter ..../typo3/alt_main.php in the URL bar
3. click on Web > Page (or any other menu item)

Expected results:
the page tree is shown, and no error messages on Firefox' error console

Actual results:
No visible result to clicks, and the following error message on the error console:

Fehler: top.rawurlencodeAndRemoveSiteUrl is not a function
Quelldatei: http://typo4test/typo3/alt_menu.php
Zeile: 266

I've tested this in the trunk and the 4.2.x branch; I don't know whether 4.1.x is affected as well.

It looks like alt_main isn't used much anymore (or we would have had this bug report much earlier), especially not by the Core developers (alt_main isn't "dog food" anymore). So I suggest to just removed alt_main and all then-unused files for 4.3. This will also make maintenance easier.
(issue imported from #M12312)