kumomta/docs/reference/mimepart/headers.md

headers

local headers = mimepart.headers

!!! note This is a field rather than a method, so you must use mimepart.headers rather than mimepart:headers to reference it.

{{since('2025.10.06-5ec871ab')}}

The headers field returns a reference to the HeaderMap for mimepart. You can use the headermap to enumerate or modify the set of headers in the mime part.

The example below prints the Subject header of the mime part:

local subject = mimepart.headers:subject()
print(subject)