Hello,
When Cache prefilling added from 2.3.0 is enabled, the following error occurs.
https://knot-resolver.readthedocs.io/en/stable/modules.html#cache-prefilling
/etc/knot-resolver # kresd -V
Knot DNS Resolver, version 2.4.0
[prefill] downloading root zone...
[prefill] saving root zone...
[    0][zimport] [zscanner] started; zone file `root.zone`
[zscanner] line: 1: parse error; code: -986 ('owner is invalid')
Segmentation fault (core dumped)
If you check the contents of the downloaded file, it seems that
something different file is being downloaded.
/etc/knot-resolver # ls -l
total 8704
-rw-------    1 root     root      12533760 Jul  8 00:24 core.64
-rw-r-----    1 root     root     3221225472 Jul  8 00:23 data.mdb
-rw-r--r--    1 1001     1001          2944 Jul  8 00:23 kresd.conf
-rw-r-----    1 root     root          8192 Jul  8 00:23 lock.mdb
-rw-r--r--    1 root     root           832 Jul  7 07:35 root.keys
-rw-r--r--    1 root     root           249 Jul  8 00:24 root.zone
drwxr-x---    2 root     root          4096 Jun 13 12:56 tty
/etc/knot-resolver # cat root.zone
<!DOCTYPE HTML PUBLIC "-//IETF//DTD HTML 2.0//EN">
<html><head>
<title>301 Moved Permanently</title>
</head><body>
<h1>Moved Permanently</h1>
<p>The document has moved <a
href="https://www.internic.net/domain/root.zone">here</a>…
</body></html>
Is this supposed behavior?
Best regards.