diff --git a/README.md b/README.md
index 10287dc..6121398 100644
--- a/README.md
+++ b/README.md
@@ -30,6 +30,10 @@ merge it yourself when you want that code in production. The split is two
 `matchBaseBranches` rules, so the same update is never offered on both
 branches. A repo using this preset therefore needs a `dev` branch.
 
+`@biomejs/biome` is held at 2.5.13 for now: 2.5.15 rewrites the quotes inside
+Svelte attribute expressions and breaks the markup. Drop the rule once a fixed
+release is out.
+
 The repo has to carry the `renovate`, `wait-3d` and `deps-code` labels before
 the first run: Renovate fails on a label that does not exist. It also has to
 have a `dev` branch, otherwise Renovate skips that base branch and code
diff --git a/default.json b/default.json
index f32a0bc..e431646 100644
--- a/default.json
+++ b/default.json
@@ -162,6 +162,13 @@
         "!docker"
       ],
       "enabled": false
+    },
+    {
+      "description": "Temporary: biome 2.5.15 rewrites quotes inside Svelte attribute expressions and breaks the markup, hold at 2.5.13 until it is fixed upstream",
+      "matchPackageNames": [
+        "@biomejs/biome"
+      ],
+      "allowedVersions": "<=2.5.13"
     }
   ]
 }