Fix: Names the Experimental ESM support warning

.yarn/versions/73a88def.yml

@@ -0,0 +1,36 @@
+releases:
+  "@yarnpkg/cli": patch
+  "@yarnpkg/core": patch
+  "@yarnpkg/plugin-pnp": patch
+
+declined:
+  - "@yarnpkg/plugin-catalog"
+  - "@yarnpkg/plugin-compat"
+  - "@yarnpkg/plugin-constraints"
+  - "@yarnpkg/plugin-dlx"
+  - "@yarnpkg/plugin-essentials"
+  - "@yarnpkg/plugin-exec"
+  - "@yarnpkg/plugin-file"
+  - "@yarnpkg/plugin-git"
+  - "@yarnpkg/plugin-github"
+  - "@yarnpkg/plugin-http"
+  - "@yarnpkg/plugin-init"
+  - "@yarnpkg/plugin-interactive-tools"
+  - "@yarnpkg/plugin-jsr"
+  - "@yarnpkg/plugin-link"
+  - "@yarnpkg/plugin-nm"
+  - "@yarnpkg/plugin-npm"
+  - "@yarnpkg/plugin-npm-cli"
+  - "@yarnpkg/plugin-pack"
+  - "@yarnpkg/plugin-patch"
+  - "@yarnpkg/plugin-pnpm"
+  - "@yarnpkg/plugin-stage"
+  - "@yarnpkg/plugin-typescript"
+  - "@yarnpkg/plugin-version"
+  - "@yarnpkg/plugin-workspace-tools"
+  - "@yarnpkg/builder"
+  - "@yarnpkg/doctor"
+  - "@yarnpkg/extensions"
+  - "@yarnpkg/nm"
+  - "@yarnpkg/pnpify"
+  - "@yarnpkg/sdks"

packages/docusaurus/docs/advanced/01-general-reference/error-codes.mdx

@@ -485,3 +485,9 @@ publish:
     - yarn config set npmAuthToken $NPM_TOKEN
     - yarn publish --provenance --tolerate-republish
 ```
+
+## YN0092 - `EXPERIMENTAL`
+
+A feature you're using depends on an experimental or unstable API provided by the underlying runtime (e.g. Node.js). While the feature works today, the API it relies on may change or be removed without notice in future runtime versions, which could lead to breakage.
+
+This is informational — everything should work correctly for now, but be aware that updates to your runtime may require corresponding updates to Yarn before the feature can continue to work as expected.

packages/plugin-pnp/sources/PnpLinker.ts

@@ -349,7 +349,7 @@ export class PnpInstaller implements Installer {
     }
 
     if (this.isEsmEnabled()) {
-      this.opts.report.reportWarning(MessageName.UNNAMED, `ESM support for PnP uses the experimental loader API and is therefore experimental`);
+      this.opts.report.reportWarning(MessageName.EXPERIMENTAL, `ESM support for PnP uses the experimental loader API and is therefore experimental`);
       await xfs.changeFilePromise(pnpPath.esmLoader, getESMLoaderTemplate(), {
         automaticNewlines: true,
         mode: 0o644,

packages/yarnpkg-core/sources/MessageName.ts

@@ -103,6 +103,7 @@ export enum MessageName {
   TIPS_NOTICE = 89,
   OFFLINE_MODE_ENABLED = 90,
   INVALID_PROVENANCE_ENVIRONMENT = 91,
+  EXPERIMENTAL = 92,
 }
 
 export function stringifyMessageName(name: MessageName | number): string {