X-robots-tag

[mobiliodevelopment]

Seems that AMPBench tool complaint if sees x-robots-tag in response:

curl -I https://www.warungtutorial.com/
HTTP/2 200
x-robots-tag: all
content-type: text/html; charset=UTF-8
expires: Fri, 08 Feb 2019 03:29:39 GMT
date: Fri, 08 Feb 2019 03:29:39 GMT
cache-control: private, max-age=0
last-modified: Fri, 08 Feb 2019 03:20:11 GMT
etag: W/"94c68ca9d0e1f69560d6da9c8be07953c9846d2fc60e727e8b5a6fd531192532"
x-content-type-options: nosniff
x-xss-protection: 1; mode=block
content-length: 0
server: GSE

message in AMPBench is:
"X-Robots-Tag Header FAIL Found header entry for X-Robots-Tagall".

All in this tag mean "index everything" so this isn't should be as error.
Values as "none" or "noindex" are the one that should be errors according to specification:
https://developers.google.com/search/reference/robots_meta_tag