Should be: fööbär
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Subject: =?US-ASCII?B?WW91ciByZWNlbnQgcHVyY2hhc2U=?=
Date: Tue,  4 Feb 2020 08:56:58 +0000
To: frank@example.com
From: admin@example.com

This is a multi-part message in MIME format.

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text: fbr
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<h1>fbr</h1>
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