"Ravi (Tom) Hale" [off-list ref] writes:
The log --format="%d" includes preceding space:
$ git log -n1 --format="XX%dXX" HEAD
XX (HEAD -> master)XX
I know of no other %<token> that is output in this way.
That is primarily because %d predates %[-+ ]<placeholder> mechanism,
I think. It is too late to redefine what "%d" means and force all
users to update their script to use "% d" instead, unfortunately.