Subject: What is /hdr/ subdirectory?

From: Hadmut Danisch <[email-masked]>
Date: Wed, 11 Mar 2026 00:28:41 +0100

Hi,

technical question because I'm hunting a bug:

In /var/spool/nncp/*/tx  there is a subdirectory  /hdr/ .

There is always a pair of files,  eg.

tx/7SM43TMJGSV3RGBZT4RPYK4XJN3HSMBGWPLEIBI2IMZPABREB4BQ
tx/hdr/7SM43TMJGSV3RGBZT4RPYK4XJN3HSMBGWPLEIBI2IMZPABREB4BQ

and I'm hunting the problem, why they do have different ownerships, the 
hdr file is owned by root and silently skipped by the daemon.

For some reason, the hdr file is generated significantly later (here: 
10min).

So my question is: What is the /hdr/ file? On what occasion is it generated?

regards

Hadmut