diff --git a/.github/workflows/size.yaml b/.github/workflows/size.yaml
index 5c2d03985be..d9aa4474dcd 100644
--- a/.github/workflows/size.yaml
+++ b/.github/workflows/size.yaml
@@ -14,4 +14,4 @@ jobs:
       - uses: preactjs/compressed-size-action@v1
         with:
           repo-token: '${{ secrets.GITHUB_TOKEN }}'
-          pattern: './{dist,es,lib}/*.js'
+          pattern: './{dist,es,lib}/*.{js,mjs}'
diff --git a/index.d.ts.REMOVED.git-id b/index.d.ts.REMOVED.git-id
index 808591b4d0c..32b24ec89bf 100644
--- a/index.d.ts.REMOVED.git-id
+++ b/index.d.ts.REMOVED.git-id
@@ -1 +1 @@
-b00c6f0885b9df7bf80500d9545dfb59f400a42c
\ No newline at end of file
+4a4d4e0ad5d994d636d2afd5192306c8dd70f596
\ No newline at end of file
diff --git a/package-lock.json.REMOVED.git-id b/package-lock.json.REMOVED.git-id
index dae1457441f..3dbc8271bcf 100644
--- a/package-lock.json.REMOVED.git-id
+++ b/package-lock.json.REMOVED.git-id
@@ -1 +1 @@
-e4462bfb499861758fc942df7c5557d153bf581d
\ No newline at end of file
+8670b475929575d312e4c3c2cb3a99c9e2bde821
\ No newline at end of file
diff --git a/package.json.REMOVED.git-id b/package.json.REMOVED.git-id
index 326da3abb2e..8e284cdaeaa 100644
--- a/package.json.REMOVED.git-id
+++ b/package.json.REMOVED.git-id
@@ -1 +1 @@
-a57914cae33a3f9e1ecd2615f109a6518f8dd023
\ No newline at end of file
+59ec76e0d31abf926e836408b9bb85245d040f44
\ No newline at end of file
diff --git a/src/createStore.js.REMOVED.git-id b/src/createStore.js.REMOVED.git-id
index 49811b6b9f2..b2a1dbc78a3 100644
--- a/src/createStore.js.REMOVED.git-id
+++ b/src/createStore.js.REMOVED.git-id
@@ -1 +1 @@
-5326a52ff8a82cca2a564d2f5b6eaf16396411f7
\ No newline at end of file
+5e64e323d14cc929593b4d0d8cac6d54836a1106
\ No newline at end of file
diff --git a/src/utils/symbol-observable.js b/src/utils/symbol-observable.js
new file mode 100644
index 00000000000..0fb198c9868
--- /dev/null
+++ b/src/utils/symbol-observable.js
@@ -0,0 +1,3 @@
+// Inlined version of the `symbol-observable` polyfill
+export default (() =>
+  (typeof Symbol === 'function' && Symbol.observable) || '@@observable')()
diff --git a/test/createStore.spec.js.REMOVED.git-id b/test/createStore.spec.js.REMOVED.git-id
index bbff797d2c4..2f4765dbaa3 100644
--- a/test/createStore.spec.js.REMOVED.git-id
+++ b/test/createStore.spec.js.REMOVED.git-id
@@ -1 +1 @@
-dcbf65cf3e5d3da0bf7bd0a1934b8951120f395c
\ No newline at end of file
+5ed9246bdc5adef07d260e6c68df755628555810
\ No newline at end of file
diff --git a/test/typescript/store.ts.REMOVED.git-id b/test/typescript/store.ts.REMOVED.git-id
index 5da42453bc9..cbae828d6f6 100644
--- a/test/typescript/store.ts.REMOVED.git-id
+++ b/test/typescript/store.ts.REMOVED.git-id
@@ -1 +1 @@
-685bfbf1b6ace275cf63208160478150ec72db79
\ No newline at end of file
+2d66396887c29d1cc4e1ed70b1087c7679b604c1
\ No newline at end of file