The Tcl::pTk that requires the Tk object is

# Tcl::pTk::libary variable: Translation from perl/tk Tk.pm
{($Tcl::pTk::library) = __FILE__ =~ /^(.*)\.pm$/;}
$Tcl::pTk::library = Tk->findINC('.') unless (defined($Tcl::pTk::libra
+ry) && -d $Tcl::pTk::library);
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$Tcl::pTk::library don't know what it is.