%P -- print percent of buffer above bottom of window, perhaps plus Top,
or print Bottom or All.
%n -- print Narrow if appropriate.
- %R -- print R or hyphen. R means that default-directory is on a
- remote machine.
%t -- visited file is text or binary (if OS supports this distinction).
%z -- print mnemonics of keyboard, terminal, and buffer coding systems.
%Z -- like %z, but including the end-of-line format.
%e -- print error message about full memory.
+ %@ -- print @ or hyphen. @ means that default-directory is on a
+ remote machine.
%[ -- print one [ for each recursive editing level. %] similar.
%% -- print %. %- -- print infinitely many dashes.
Decimal digits after the % specify field width to which to pad. */);