diff --git a/docs/source/yosys_internals/extending_yosys/index.rst b/docs/source/yosys_internals/extending_yosys/index.rst
index 2a4d2dfef..88f36d526 100644
--- a/docs/source/yosys_internals/extending_yosys/index.rst
+++ b/docs/source/yosys_internals/extending_yosys/index.rst
@@ -10,5 +10,6 @@ of interest for developers looking to customise Yosys builds.
 
    extensions
    build_verific
+   functional_ir
    test_suites