When Rmail displays a message that does not fit on the screen, you must scroll through it to read the rest. You could do this with C-v, M-v and M-<, but in Rmail scrolling is so frequent that it deserves to be easier to type.
scroll-up).
scroll-down).
rmail-beginning-of-message).
Since the most common thing to do while reading a message is to scroll
through it by screenfuls, Rmail makes SPC and DEL synonyms of
C-v (scroll-up) and M-v (scroll-down)
The command . (rmail-beginning-of-message) scrolls back to the
beginning of the selected message. This is not quite the same as M-<:
for one thing, it does not set the mark; for another, it resets the buffer
boundaries to the current message if you have changed them.
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