For context, see testing overview.

This document is encoded in ISO-8859-13:

$ document.characterSet
"ISO-8859-13"

When href attributes are encoded for use in HTTP, the pathname is encoded in UTF-8, but the search part is encoded with ISO-88590-13:

$ a = document.createElement('a'); null
$ zz = String.fromCharCode(parseInt("017D", 16)); null
$ a.href = "http://example/" + zz + "?" + zz; null
$ a.pathname
"/%C5%BD"
$ a.search
"?%DE"

See also:

• Bug 284474 - Converting to UTF-8 a url with an unescaped non-ASCII chars in the query part leads to an incompatibility with most server-side programs
  reported 2005-03-02
  RESOLVED FIXED 2005-10-10
• public-html discussion June 2008