diff --git a/feature-group-definitions/masonry.yml b/feature-group-definitions/masonry.yml
new file mode 100644
index 00000000000..bf2380d4db8
--- /dev/null
+++ b/feature-group-definitions/masonry.yml
@@ -0,0 +1,7 @@
+spec: https://drafts.csswg.org/css-grid-3/
+compat_features:
+  - css.properties.align-tracks
+  - css.properties.grid-column-rows.masonry
+  - css.properties.grid-template-rows.masonry
+  - css.properties.justify-tracks
+  - css.properties.masonry-auto-flow
diff --git a/feature-group-definitions/subgrid.yml b/feature-group-definitions/subgrid.yml
index 9cce8422c84..4837c121315 100644
--- a/feature-group-definitions/subgrid.yml
+++ b/feature-group-definitions/subgrid.yml
@@ -1,2 +1,5 @@
 spec: https://drafts.csswg.org/css-grid-2/#subgrids
 caniuse: css-subgrid
+compat_features:
+  - css.properties.grid-template-columns.subgrid
+  - css.properties.grid-template-rows.subgrid