diff --git a/dvc/render/match.py b/dvc/render/match.py
index de43d9a66..b93d22654 100644
--- a/dvc/render/match.py
+++ b/dvc/render/match.py
@@ -35,8 +35,8 @@ class PlotsData:
     def group_definitions(self):
         groups = defaultdict(list)
         for rev, rev_content in self.data.items():
-            for _config_file, config_file_content in (
-                rev_content.get("definitions", {}).get("data", {}).items()
+            for config_file_content in (
+                rev_content.get("definitions", {}).get("data", {}).values()
             ):
                 for plot_id, plot_definition in config_file_content.get(
                     "data", {}