The source project of this merge request has been removed.
Decode base64 encoded e-mail attachment filename.
According to RFC 2231 the filename of e-mail attachments can be encoded, e.g. with base64 (for example, the Brother ADS2800W Scanner does this).
Here an example how it looks like:
Content-Disposition: attachment; filename="=?UTF-8?B?QlJXMjg1NjVBOEI5RkQyXzIwMTcwNTIzXzIzMDMzN18wMDAzMDMucGRm?="
This merge request handles this situation. It also has a test case.