encoding
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... Text/Plain, and,
in the presence of this parameter, the use of trailing whitespace to
indicate flowed lines. This results in an encoding which appears as
normal Text/Plain in older implementations, since it is in fact
...
...
[Quoted-Printable] encoding SHOULD NOT be used with Format=Flowed
unless absolutely necessary (for example, non-US-ASCII (8-bit ...
... line breaks, space-stuffing,
and [Quoted-Printable] encoding (to protect soft line breaks) before
being digitally signed or encrypted ...
... applying format=flowed in these cases, as format=fixed combined with
quoted-printable encoding may be more suitable.
...