Some nokogiri-dependent code works for Ruby >= 2.7.

lib/rdf/microdata/rdfa_reader.rb

@@ -97,7 +97,6 @@ def initialize(input = $stdin, **options, &block)
             # Add @vocab to referenced using the closest ansestor having @vocab of item.
             # If the element with id reference has no resource attribute, add a resource attribute whose value is a NUMBER SIGN U+0023 followed by reference to the element.
             # If the element with id reference has no typeof attribute, add a typeof="rdfa:Pattern" attribute to the element.
-            # FIXME: This broke in Nokogiri 13.0
             referenced.wrap(%(<div vocab="#{item_vocab}" resource="##{ref}" typeof="rdfa:Pattern" />))
 
             # Add a link child element to the element that represents the item, with a rel="rdfa:copy" attribute and an href attribute whose value is a NUMBER SIGN U+0023 followed by reference

spec/rdfa_reader_spec.rb

@@ -630,6 +630,7 @@
         ],
       }.each do |name, (md, nt)|
         it "parses #{name}" do
+          pending "Broke in Nokogiri 13.0" if RUBY_VERSION < "2.7"
           expect(parse(md)).to be_equivalent_graph(nt, logger: @logger)
         end
       end