why does git-send-email unwrap headers?

Hello:

I've noticed that when a message is sent with git-send-email, it will unwrap
all existing headers into a single line, such that:

    Some-header: This is a long header that happens to be longer than 78
     characters and is therefore wrapped at whitespace chars to properly span
     across multiple lines

becomes:

    Some-header: This is a long header that happens to be longer than 78 characters and is therefore wrapped at whitespace chars to properly span across multiple lines

While it's not *wrong* (the 78-character limit is from a very old RFC), I'm
curious if this is intentional or just an oversight.

-K