diff --git a/otc_metadata/data/services.yaml b/otc_metadata/data/services.yaml
index 9ed2a687..ba5e83a1 100644
--- a/otc_metadata/data/services.yaml
+++ b/otc_metadata/data/services.yaml
@@ -13,6 +13,9 @@
 
 # Please consult with otc_metadata.services.Services:_sort_data for expected
 # sort order. When unsure perform tools/sort_metadata.py for getting it sorted.
+# It is also supported, that content of files under
+# documents/services/service_categories is being merged with
+# the content here.
 ---
 documents: []
 service_categories: []