diff --git a/babel.spec b/babel.spec
index 42eddff..5398b65 100644
--- a/babel.spec
+++ b/babel.spec
@@ -28,6 +28,9 @@ BuildRequires:  python3-devel
 
 %if %{without bootstrap}
 BuildRequires:  coreutils
+# The Python test dependencies are not generated from tox.ini,
+# because it would require complex patching to be usable
+# and becasue we want to avoid the tox dependency in ELN/RHEL.
 BuildRequires:  python3-pytest
 BuildRequires:  python3-freezegun
 %if %{with pytz_tests}