Comment 11 for bug 571286

> d) each mail client and groupware and essentially any addressbook software
> on the market can handle vcard, and vcard does not have such a silly ext thingy

See RFC 2426, par. 3.2.1, "ADR Type Definition" <http://tools.ietf.org/html/rfc2426#section-3.2.1>:

"The structured type value corresponds, in sequence, to the post office box; the extended address; the street address; the locality (e.g., city); the region (e.g., state or province); the postal code; the country name."

Also par. 4, "Formal grammar":

"adr-value = 0*6(text-value ";") text-value
        ; PO Box, Extended Address, Street, Locality, Region, Postal
        ; Code, Country Name"