diff --git a/docs/sphinx/README.md b/docs/sphinx/README.md
index cbd2627cc..6699a514e 100644
--- a/docs/sphinx/README.md
+++ b/docs/sphinx/README.md
@@ -2,3 +2,4 @@
 
 * `source`: A folder for all source files of the **Sphinx** documentation builder
   * `conf.py`: Configuration file for **Sphinx**
+  * `index.rst`: index of all documentations for for **Sphinx**