经过定位问题发现从，从火狐8开始，双引号作为分隔符被弃用，详细说明见：
https://developer.mozilla.org/en/Firefox_8_for_developers#section_6
https://bugzilla.mozilla.org/show_bug.cgi?id=651185

具体为QQ邮箱下载大附件时重定向到链接：
http://sz.mail.store.qq.com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
响应头信息包含：
Content-Disposition: attachment; filename*="UTF-8''soft wiper_PROSPORT_fin.jpg"

由于filename说明中带有双引号，无法识别处文件名称，所以火狐默认采用链接名作为文件名：
“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”

正确做法为，应该去掉前后两个双引号，修改为：
Content-Disposition: attachment; filename*=UTF-8''soft wiper_PROSPORT_fin.jpg