SecAuditLogParts never logs anything for 'K' type (list of rule IDs)

Describe the bug

I want to analyse POST body content but I don't want to print any POST body content (or any actual data snippets from the request, such as cookies etc) to the log file. So I don't want to log 'B', 'C', 'F', 'H', 'J' etc.

I just want to get the time of the event and the rule ID that tripped the blocked request.

I believe the 'K' type in SecAuditLogParts is meant to log the rule ID

https://github.com/SpiderLabs/ModSecurity/wiki/Reference-Manual-(v3.x)#SecAuditLogParts

However, in all my logs, the 'K' is always empty. The only meaningful data I can get about the rules that tripped is from 'H', but it contains too many other messages in that log entry such as personal data, which I can't put in logs.

Logs and dumps

Example:

---0s7Btvlo---A--
[17/Feb/2022:02:39:54 +0000] 1645065594 10.42.0.11 0 172.17.0.3 80

---0s7Btvlo---K--

---0s7Btvlo---Z--

To Reproduce

Steps to reproduce the behavior:

Set SecAuditLogParts to 'AKZ' and you'll never get entries for 'K'.

Expected behavior

I should get the rule ID or something like that (? since it's never worked, I don't know what it looks like) when logging K.

Server

• ModSecurity version: libmodsecurity 3.0.6 (commit hash c3d7f4b560797a052681dcffb97a22bb906487cd), ModSecurity-nginx v1.0.2
• WebServer Nginx 1.14.0 (the official debian package 1.14.0-0ubuntu1.9 from on Ubuntu 18.04)
• OS (and distro): Ubuntu Linux 18.04 LTS

Rule Set

• public coreruleset 3.3.2

No source file or test is named. Start by reproducing the issue with SecAuditLogParts set to AKZ on the stated ModSecurity-nginx setup, then trace the audit-log handling for the K part. Done means K contains the triggered rule ID while omitting the sensitive request data described in the report, with regression coverage for the behavior.