diff --git a/lib/modules/versioning/ubuntu/readme.md b/lib/modules/versioning/ubuntu/readme.md
new file mode 100644
index 0000000000000000000000000000000000000000..38b330179378d089d71711b99001cad53b348a9d
--- /dev/null
+++ b/lib/modules/versioning/ubuntu/readme.md
@@ -0,0 +1,4 @@
+Ubuntu versioning is used for Ubuntu container images that are referenced by their release version or a codename.
+
+Versions to which this scheme applies are e.g. `22.04` and `jammy`.
+Container image tags such as `jammy-20220815` or `focal-20220826` are not compliant with the current implementation.