The man page of git-fast-import says the syntax is "'option' SP <option> LF". But this is wrong, and commands like that will be silently ignored. fast-import.c only parses commands starting with "option git ", and ignores others starting with "option ". See https://github.com/git/git/blob/027a3b943b444a3e3a76f9a89803fc10245b858f/fast-import.c#L3487-L3490 . The correct syntax is e.g. "option git stats" or "option git big-file-threshold=123". The docs should say "'option' SP 'git' SP <option> LF" or maybe even "'option' SP 'git' SP <option> ('=' <argument>)? LF" (similarly to the docs for feature), and explain this is meant to allow other consumers of the fast import format. Looks like this bug existed since the option command was added in 9c8398f in 2009. Am I the first one who tried to use it? ;-) Cheers, Tomi