diff --git a/doc_src/conf.py b/doc_src/conf.py
index 52ac617b7..accb26bdf 100644
--- a/doc_src/conf.py
+++ b/doc_src/conf.py
@@ -16,10 +16,6 @@ from docutils import nodes
 
 try:
     import sphinx_markdown_builder
-
-    extensions = [
-        "sphinx_markdown_builder",
-    ]
 except ImportError:
     pass