Another method is to form queries targeting the item of interest, parse, then use "findvalue":

my $xquery =  '//metadata/audience/@name';# find the first <audience n
+ame="xyz">    
my $xquery2 = "//othermeta[\@name = 'plugin.id']/\@content";# find an 
+othermeta with a name = plugin.id and @content 
my $xquery3 = '//@xml:lang'; # find first @xml:lang

my $xparser = XML::LibXML->new();  # create new parser object
     
eval { $xmldoc = $xparser->parse_file($file) };  # trap parsing errors
+ that can't be suppressed normally, like &nbsp; entities
if ($@){
    print "Problems!  \n The error(s):\n$@\n";  
}
             
if ($pluginname = $xmldoc->findvalue( $xquery2 )){    # returns value 
+of plugin name
    print " Plugin name found: $pluginname\n";
}
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ETC...