diff --git a/lib/modules/manager/html/readme.md b/lib/modules/manager/html/readme.md
index f8291240bb255b5e3d77065cea2fab12ca5eab5c..a238a1cf242fd4d253b2e7272607ee01862e9643 100644
--- a/lib/modules/manager/html/readme.md
+++ b/lib/modules/manager/html/readme.md
@@ -1 +1,7 @@
-The `html` manager extracts scripts and CSS includes pointing to cdnjs. It differs from the `cdnjs` manager in that it detects if an integrity hash is already present and updates it too if found.
+The `html` manager updates `<script>` tags and CSS `<link>` tags that point to the [cdnjs content delivery network](https://cdnjs.com/).
+It also updates Subresource Integrity (SRI) hashes in `integrity` attributes.
+
+Key differences between the `cdnurl` manager and the `html` manager:
+
+- The `html` manager updates SRI hashes, the `cndurl` manager does not
+- The `html` manager automatically finds some files to update, the `cndurl` manager must be given a `fileMatch`