There are few reasons superserver API is not publicly documented, one of them is to prevent an easy discoverability of outdated instances outside firewalls by hackers. You can use Atelier API with relatively recent Cache/IRIS, which answers on Web server port and has support for authentication and will return version of Cache/IRIS it's running on, for example:

You can also try to ask WRC privately if above option is not suitable for any reason.

You can try using DBF utility from my old Cache-based framework:

https://github.com/logist/p6/blob/master/classes/p6/Dbf.xml

It has ReadFile/ReadStream & WriteFile/WriteStream methods

Usage:

set sc=##class(p6.Dbf).WriteFile(file,array)
sc - execution status %Status
file-file name
array - string containing a name of global with data,
 
for example: ^asd("asdf"),
^CacheTemp($job,"dbf")
this array has to provide the following structure
...,"header")=<header>
format $list($list(var1,length1,type1,dec1),...,$list(varN,lengthN,typeN,decN)); type is D for date N for number anything else for string
...,"row",<row number>)=<data>

data format $list(var1,...,varN)

This is what I do to generate JWTs.

ClassMethod GetJWT(username As %String) As %String
{
// Calculate the issued at and expiration dates
set iat = ##class(%OAuth2.Utils).TimeInSeconds($ztimestamp,0)
set exp = ##class(%OAuth2.Utils).TimeInSeconds($ztimestamp,3600*24*7)
 
// Define token payload
set payload = {
"iat": (iat),
"iss": "zpmhub",
"exp": (exp),
"user": (username)
}
set secret=$get(^JWTSecret)
if secret="" {
set secret=##class(%PopulateUtils).StringMin(64,64)
set secret=$tr($p($SYSTEM.Encryption.Base64Encode(secret,1),"=",1),"+/","-_")
set ^JWTSecret=secret
}
set JOSE("sigalg")="HS256"
do ##class(%OAuth2.JWKS).AddOct("HS256",secret,.RemotePrivate)
do ##class(%OAuth2.JWT).ObjectToJWT(.JOSE,payload,,.RemotePrivate,.jwt)
quit jwt
}