Problem Description

I need to modify the "part" headers in a multipart/form-data request.
(Common use-case: to alter the file name and/or content-type of an uploaded file).

I see an option to edit "multipart form", but it only allows changing the "key" (value of Content-Disposition: ... name) and part contents, but not the headers.

Is a feature to show / edit headers in "multipart" requests actually missing, or am I just misusing it?

I thought I'd ask here before I start digging in the code. If the feature is actually missing, I'm willing to contribute it if it's something that would interest the project.

Proposal

Add support for modifying part headers in a multipart/form-data request from the mitmproxy UI.

Alternatives

I'm currently exporting / modifying externally / reimporting / replaying HAR files as a workaround currently, but it's fairly clumsy and it doesn't work for modifying "intercepted" requests on the fly.

Additional context

I can add screenshots if clarification is needed.