diff --git a/.changeset/loud-doors-think.md b/.changeset/loud-doors-think.md
new file mode 100644
index 0000000000..a2dccc1e08
--- /dev/null
+++ b/.changeset/loud-doors-think.md
@@ -0,0 +1,6 @@
+---
+'@urql/core': patch
+'@urql/exchange-graphcache': patch
+---
+
+Make the extension of the main export unknown, which fixes a Webpack issue where the resolver won't pick `module` fields in `package.json` files once it's importing from another `.mjs` file.
diff --git a/exchanges/graphcache/extras/package.json b/exchanges/graphcache/extras/package.json
index 66dde24a6b..0e0d5fc3bd 100644
--- a/exchanges/graphcache/extras/package.json
+++ b/exchanges/graphcache/extras/package.json
@@ -1,7 +1,7 @@
 {
   "name": "urql-exchange-graphcache-extras",
   "private": true,
-  "main": "../dist/urql-exchange-graphcache-extras.js",
+  "main": "../dist/urql-exchange-graphcache-extras",
   "module": "../dist/urql-exchange-graphcache-extras.mjs",
   "types": "../dist/types/extras/index.d.ts",
   "source": "../src/extras/index.ts",
diff --git a/packages/core/internal/package.json b/packages/core/internal/package.json
index a388e9cdb3..033f2f5526 100644
--- a/packages/core/internal/package.json
+++ b/packages/core/internal/package.json
@@ -1,7 +1,7 @@
 {
   "name": "urql-core-internal",
   "private": true,
-  "main": "../dist/urql-core-internal.js",
+  "main": "../dist/urql-core-internal",
   "module": "../dist/urql-core-internal.mjs",
   "types": "../dist/types/internal/index.d.ts",
   "source": "../src/internal/index.ts",