... in the page title, and in the body: äöüßÄÖÜ

Other accents too:áéíóú

[RS] adds all of the iso8859-1 characters above 160, for even heavier testing:
 160:  ¡¢£¤¥¦§¨©ª«¬��®¯
 176: °±²³´µ¶·¸¹º»¼½¾¿
 192: ÀÁ����ÄÅÆÇÈÉÊËÌÍÎÏ
 208: ÐÑÒÓÔÕÖ×ØÙÚÛÜÝÞß
 224: àáâãäåæçèéêëìíîï
 240: ðñòóôõö÷øùúûüýþÿ

[KBK] edits the page to see whether the characters get damaged in the round trip.

[mjk] I can promise, that in this Wiki will visit some browsers, that will convert ISO-8859-1 characters to UTF-8. You can find my little rant from my user information page. Unfortunately, I'm yet unable to identify, which browsers change character encoding.

Let's test links: [testing umlauts: äöüßÄÖÜ]... Moo!