Problem with saving an attached file with a Cyrillic name from mail to files.

Hello, dear developers!

When saving a file with a Cyrillic name, the file name looks like it was in the mail headers.

Content-Type: application/vnd.openxmlformats-officedocument.wordprocessingml.document;
 name="=?utf-8?B?0J/Qu9Cw0L0g0YDQsNCx0L7RgiDQv9C+INGB0L7Qt9C00LDQvdC40Y4g0LXQtNC40L3QvtCz0L4g0YLQtdGA0YDQuNGC0L7RgNC40LDQu9GM0L3Qvi3RgNCw0YHQv9GA0LXQtNC10LvQtdC90L3QvtCz0L4g0KbQntCUINCT0Jog0JzQkNCh0JrQntCcLmRvY3g=?="
Content-Disposition: attachment;
 filename="=?utf-8?B?0J/Qu9Cw0L0g0YDQsNCx0L7RgiDQv9C+INGB0L7Qt9C00LDQvdC40Y4g0LXQtNC40L3QvtCz0L4g0YLQtdGA0YDQuNGC0L7RgNC40LDQu9GM0L3Qvi3RgNCw0YHQv9GA0LXQtNC10LvQtdC90L3QvtCz0L4g0KbQntCUINCT0Jog0JzQkNCh0JrQntCcLmRvY3g=?="
Content-Transfer-Encoding: base64

Thank you.