Boundary with several names

Sample_1

User-Agent: Roundcube Webmail/0.4

--=_Boundary_Id
Content-Transfer-Encoding: base64
Content-Type: application/pdf; charset=binary; charset=UTF-8;
 name=File.ext
Content-Disposition: attachment;
 filename=File.ext
 
=====================================

User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:12.0) Gecko/20120428
 Thunderbird/12.0.1
 
--Boundary_(Boundary_Id)
Content-type:
 application/vnd.openxmlformats-officedocument.wordprocessingml.document;
 name="=?KOI8-R?Q?=E3=F0=F0=EB=5F=EF=F4=5F=EC=C9=C3=C5=CE=DA=C9=C9_=CE=C1_=F0?=
 =?KOI8-R?Q?=EF=2Edocx?="
Content-transfer-encoding: base64
Content-disposition: attachment;
 filename="=?KOI8-R?Q?=E3=F0=F0=EB=5F=EF=F4=5F=EC=C9=C3=C5=CE=DA=C9=C9_=CE=C1_=F0?=
 =?KOI8-R?Q?=EF=2Edocx?=";
 filename*0*=KOI8-R''%E3%F0%F0%EB%5F%EF%F4%5F%EC%C9%C3%C5%CE%DA%C9%C9%20%CE;
 filename*1*=%C1%20%F0%EF%2E%64%6F%63%78