[bakql]

This seems like a convoluted way of adding a new header, at least compared to the http servers I know. Why is that? Maybe postfix is not the appropriate place to make this change and that’s why there’s no option to just add a new header?

[noja]

One line is convoluted?

[mort96]

It's convoluted that it's a sed-style regex operating on textual headers instead of just ... an option to add a header