diff --git a/testing/web-platform/meta/css/css-env/env-in-custom-properties.tentative.html.ini b/testing/web-platform/meta/css/css-env/env-in-custom-properties.tentative.html.ini
new file mode 100644
index 0000000000000..e1a38c0602100
--- /dev/null
+++ b/testing/web-platform/meta/css/css-env/env-in-custom-properties.tentative.html.ini
@@ -0,0 +1,4 @@
+[env-in-custom-properties.tentative.html]
+  [Substitution of unrecognized env() causes unset]
+    expected: FAIL
+
diff --git a/testing/web-platform/meta/css/css-variables/variable-substitution-variable-declaration.html.ini b/testing/web-platform/meta/css/css-variables/variable-substitution-variable-declaration.html.ini
new file mode 100644
index 0000000000000..9e37f67272126
--- /dev/null
+++ b/testing/web-platform/meta/css/css-variables/variable-substitution-variable-declaration.html.ini
@@ -0,0 +1,4 @@
+[variable-substitution-variable-declaration.html]
+  [target10 --varC]
+    expected: FAIL
+
diff --git a/testing/web-platform/meta/css/css-variables/variables-substitute-guaranteed-invalid.html.ini b/testing/web-platform/meta/css/css-variables/variables-substitute-guaranteed-invalid.html.ini
new file mode 100644
index 0000000000000..a8dfa9b3172f2
--- /dev/null
+++ b/testing/web-platform/meta/css/css-variables/variables-substitute-guaranteed-invalid.html.ini
@@ -0,0 +1,7 @@
+[variables-substitute-guaranteed-invalid.html]
+  [A custom property referencing a cycle is treated as unset]
+    expected: FAIL
+
+  [A custom property referencing a non-existent variable is treated as unset]
+    expected: FAIL
+