(merge 39bb692152 rs/imap-send-use-xsnprintf later to maint).
(merge 8d320cec60 jc/t2104-style-fixes later to maint).
(merge b4454d5a7b pw/t3428-cleanup later to maint).
+ (merge 84a7c33a4b pf/commitish-committish later to maint).
+ (merge 8882ee9d68 la/mailmap-entry later to maint).