diff --git a/resources/subjectscheme-outputclass.ditamap b/resources/subjectscheme-outputclass.ditamap
index 3b1d02be..2a7683ed 100644
--- a/resources/subjectscheme-outputclass.ditamap
+++ b/resources/subjectscheme-outputclass.ditamap
@@ -64,6 +64,11 @@
       <subjectdef keys="language-svg"/>
       <subjectdef keys="language-xml"/>
       <subjectdef keys="language-yaml"/>
+      <!-- Fenced code blocks in GitHub wiki -->
+      <subjectdef keys="java"/>
+      <subjectdef keys="markdown"/>
+      <subjectdef keys="xml"/>
+      <subjectdef keys="yaml"/>
     </subjectdef>
     <subjectdef keys="codeblock-syntax">
       <topicmeta>