This procedure is defined in the server but not documented via ad_proc or proc_doc and may be intended as a private interface.
The procedure is defined as:
proc ::xowiki::validate_form_form {} { upvar form form if {$form eq ""} {return 1} dom parse -simple -- [lindex $form 0] doc $doc documentElement root return [expr {$root ne "" && [$root nodeName] eq "form"}] }