base-64 ignored

The following email from a business is not being decoded.
------=_Part_29546_1281477845.1653517724260
MIME-Version: 1.0
Content-Type: text/html; charset="utf-8"
Content-Transfer-Encoding: base64

77u/
Cgo8IURPQ1RZUEUgaHRtbCBQVUJMSUMgIi0vL1czQy8vRFREIFhIVE1MIDEuMCBUcmFuc2l0

+83k of additional data, ending in:

------=_Part_29546_1281477845.1653517724260--

Why?

Thanks.

Cheers, Gene Heskett.
-- 
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author, 1940)
If we desire respect for the law, we must first make the law respectable.
 - Louis D. Brandeis