The asterisk ("*", ASCII 2A hex) and exclamation mark ("!" , ASCII 21 hex) are reserved for use as having special signifiance within specific schemes.
http://www.w3.org/Addressing/URL/uri-spec.html
http://www.w3.org/Addressing/URL/uri-spec.html
Hvězdička v URL odkazu?
http://www.w3.org/Addressing/URL/uri-spec.html