test case 5.
list's language : fr (iso-8859-1)
sender's language : ja (euc-jp, out going messages are encoded to iso-2022-jp)
sender's display name: =?ISO-2022-JP?B?GyRCRnNMWkx3P04bKEI=?=
(results)
From: =?utf-8?b?5LqM5pyo6Z2W5LuBIHZpYSBNYWlsbWFuLXRlc3Q=?= <...>
test case 5. JP?B?GyRCRnNMWk x3P04bKEI= ?= b?5LqM5pyo6Z2W5 LuBIHZpYSBNYWls bWFuLXRlc3Q= ?= <...>
list's language : fr (iso-8859-1)
sender's language : ja (euc-jp, out going messages are encoded to iso-2022-jp)
sender's display name: =?ISO-2022-
(results)
From: =?utf-8?
is a rational results, I think.