Can optionally specify additional options directly to mysqldump if there is no native Holland option for it."
That said, I wonder if it would be better to use the latter syntax (if possible) as it feels more like what you would put on the command-line? Otherwise, yes, this needs updating and clarification.
Online docs (1.0 and 1.1) are also a bit vague:
"additional-options = <mysqldump arguments>
Can optionally specify additional options directly to mysqldump if there is no native Holland option for it."
That said, I wonder if it would be better to use the latter syntax (if possible) as it feels more like what you would put on the command-line? Otherwise, yes, this needs updating and clarification.