[moving to fpc-other because this has nothing to do with Pascal programming]

waldo kitty wrote

how can my copy be different from your copy if everyone in the list gets a copy of the same message via the same originating source from the same originating writer's software?

Mime types enable intermediate mail servers to change the content transfer encoding for whatever reason, since this encoding is part of the message and hence in theory it can be safely changed. And it's clear there were differences in this case because Johannes' copy was base64-encoded and mine wasn't.

Jonas