The
extension code macro describes the source parameter to show property values.
An attempt with something like
{{code source="object_property:XWiki.IFrameMacro.XWiki.WikiMacroClass.code" / }}
produces an irritating error message “Current user is not allowed to access document[…with the reference to the document containing the request …]”
I suppose I misunderstand the syntax.
The problem is not to get the result as I can do with calls like
{{groovy}}
"{{code}}"+xwiki.getDocument("XWiki.IFrameMacro").getObject("XWiki.WikiMacroClass").get("code")+"{{/code}}"
{{/groovy}}
or
{{velocity}}
{{code}}$xwiki.getDocument("XWiki.IFrameMacro").getObject("XWiki.WikiMacroClass").get("code"){{/code}}
{{/velocity}}
but using standard macros seems to me to be a better solution for documentation tasks.