diff --git a/script/hassfest/manifest.py b/script/hassfest/manifest.py
index 4861c893a37..54ae65e6727 100644
--- a/script/hassfest/manifest.py
+++ b/script/hassfest/manifest.py
@@ -122,6 +122,9 @@ NO_DIAGNOSTICS = [
     "geonetnz_quakes",
     "google_assistant_sdk",
     "hyperion",
+    # Modbus is excluded because it doesn't have to have a config flow
+    # according to ADR-0010, since it's a protocol integration. This
+    # means that it can't implement diagnostics.
     "modbus",
     "nightscout",
     "pvpc_hourly_pricing",