diff --git a/_Sidebar.md b/_Sidebar.md
index ed172bf..42b1246 100644
--- a/_Sidebar.md
+++ b/_Sidebar.md
@@ -16,4 +16,7 @@
 
 [[Appendix C: Firmware programming]]
 
-[[Appendix D: Hardware]]
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+[[Appendix D: Hardware]]
+
+# Legal
+[[GNU Free Documentation License]]
\ No newline at end of file