[dns-operations] What is the reason of J-Root doesn't serve the arpa zone?

[John Levine]

It appears that Stephane Bortzmeyer <bortzmeyer at nic.fr> said:
>On Mon, Dec 06, 2021 at 01:42:42AM +0900,
> Yasuhiro Orange Morishita / 森下泰宏 <yasuhiro at jprs.co.jp> wrote 
> a message of 89 lines which said:
>
>> And I heard from another person that J-Root holds the arpa zone, but
>> not delegated.  It is also interesting.
>
>Indeed. It is funny.

It gets funnier:

$ dig @j.root-servers.net soa arpa

; <<>> DiG 9.10.6 <<>> @j.root-servers.net soa arpa
; (2 servers found)
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 436

;; flags: qr aa rd; QUERY: 1, ANSWER: 1, AUTHORITY: 12, ADDITIONAL: 1
;; WARNING: recursion requested but not available

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 1232
;; QUESTION SECTION:
;arpa.				IN	SOA

;; ANSWER SECTION:
arpa.			86400	IN	SOA	a.root-servers.net. nstld.verisign-grs.com. 2021120501 1800 900 604800 86400

;; AUTHORITY SECTION:
arpa.			518400	IN	NS	a.root-servers.net.
arpa.			518400	IN	NS	b.root-servers.net.
arpa.			518400	IN	NS	c.root-servers.net.
arpa.			518400	IN	NS	d.root-servers.net.
arpa.			518400	IN	NS	e.root-servers.net.
arpa.			518400	IN	NS	f.root-servers.net.
arpa.			518400	IN	NS	g.root-servers.net.
arpa.			518400	IN	NS	h.root-servers.net.
arpa.			518400	IN	NS	i.root-servers.net.
arpa.			518400	IN	NS	k.root-servers.net.
arpa.			518400	IN	NS	l.root-servers.net.
arpa.			518400	IN	NS	m.root-servers.net.

;; Query time: 85 msec
;; SERVER: 2001:503:c27::2:30#53(2001:503:c27::2:30)
;; WHEN: Sun Dec 05 14:05:32 EST 2021
;; MSG SIZE  rcvd: 299