mu4e supports a number of marks:
mark for/as | keybinding | description
-------------+-------------+------------------------------
'something' | *, <insert> | mark now, decide later
delete | D, <delete> | delete
flag | + | mark as 'flagged' ('starred')
move | m | move to some maildir
read | ! | mark as read
refile | r | mark for refiling
trash | d | move to the trash folder
untrash | = | remove 'trash' flag
unflag | - | remove 'flagged' mark
unmark | u | remove mark at point
unmark all | U | remove all marks
unread | ? | marks as unread
action | a | apply some action
|
After marking a message, the left-most columns in the headers view indicate
the kind of mark. This is informative, but if you mark many (say, thousands)
messages, this slows things down significantly14. For this reason, you can disable this by setting
mu4e-headers-show-target to nil.
something is a special kind of mark; you can use it to mark messages
for ‘something’, and then decide later what the ‘something’ should
be15 Later, you can set the actual mark
using M-x mu4e-mark-resolve-deferred-marks
(#). Alternatively, mu4e will ask you when you try to execute
the marks (x).
this uses an Emacs feature called overlays, which are slow when used a lot in a buffer
This kind of ‘deferred marking’ is similar to the facility
in dired, midnight commander
(https://www.midnight-commander.org/) and the like, and uses the
same key binding (insert).