diff --git a/extensions/merge-conflict/extension-browser.webpack.config.js b/extensions/merge-conflict/extension-browser.webpack.config.js
new file mode 100644
index 00000000000..3bc5f783258
--- /dev/null
+++ b/extensions/merge-conflict/extension-browser.webpack.config.js
@@ -0,0 +1,33 @@
+/*---------------------------------------------------------------------------------------------
+ *  Copyright (c) Microsoft Corporation. All rights reserved.
+ *  Licensed under the MIT License. See License.txt in the project root for license information.
+ *--------------------------------------------------------------------------------------------*/
+
+//@ts-check
+
+'use strict';
+
+const withDefaults = require('../shared.webpack.config');
+const path = require('path');
+
+const clientConfig = withDefaults({
+	target: 'webworker',
+	context: __dirname,
+	entry: {
+		extension: './src/mergeConflictMain.ts'
+	},
+	output: {
+		filename: 'mergeConflictMain.js'
+	},
+	performance: {
+		hints: false
+	},
+	resolve: {
+		alias: {
+			'vscode-nls': path.resolve(__dirname, '../../build/polyfills/vscode-nls.js')
+		}
+	}
+});
+clientConfig.module.rules[0].use.shift(); // remove nls loader
+
+module.exports = clientConfig;
diff --git a/extensions/merge-conflict/extension.webpack.config.js b/extensions/merge-conflict/extension.webpack.config.js
index 45600607fc5..7a04ca98e97 100644
--- a/extensions/merge-conflict/extension.webpack.config.js
+++ b/extensions/merge-conflict/extension.webpack.config.js
@@ -12,6 +12,9 @@ const withDefaults = require('../shared.webpack.config');
 module.exports = withDefaults({
 	context: __dirname,
 	entry: {
-		extension: './src/extension.ts'
-	}
+		extension: './src/mergeConflictMain.ts'
+	},
+	output: {
+		filename: 'mergeConflictMain.js'
+	},
 });
diff --git a/extensions/merge-conflict/package.json b/extensions/merge-conflict/package.json
index 815a412492a..f59738d3008 100644
--- a/extensions/merge-conflict/package.json
+++ b/extensions/merge-conflict/package.json
@@ -16,7 +16,8 @@
   "activationEvents": [
     "*"
   ],
-  "main": "./out/extension",
+  "main": "./out/mergeConflictMain",
+  "browser": "./dist/mergeConflictMain",
   "scripts": {
     "compile": "gulp compile-extension:merge-conflict",
     "watch": "gulp watch-extension:merge-conflict"
diff --git a/extensions/merge-conflict/src/commandHandler.ts b/extensions/merge-conflict/src/commandHandler.ts
index f79c6650af0..ca45b9a16f8 100644
--- a/extensions/merge-conflict/src/commandHandler.ts
+++ b/extensions/merge-conflict/src/commandHandler.ts
@@ -5,7 +5,6 @@
 import * as vscode from 'vscode';
 import * as interfaces from './interfaces';
 import ContentProvider from './contentProvider';
-import * as path from 'path';
 import { loadMessageBundle } from 'vscode-nls';
 const localize = loadMessageBundle();
 
@@ -86,7 +85,6 @@ export default class CommandHandler implements vscode.Disposable {
 	}
 
 	async compare(editor: vscode.TextEditor, conflict: interfaces.IDocumentMergeConflict | null) {
-		const fileName = path.basename(editor.document.uri.fsPath);
 
 		// No conflict, command executed from command palette
 		if (!conflict) {
@@ -134,6 +132,8 @@ export default class CommandHandler implements vscode.Disposable {
 			conflict.range.start.line - mergeConflictLineOffsets, conflict.range.start.character
 		);
 
+		const docPath = editor.document.uri.path;
+		const fileName = docPath.substring(docPath.lastIndexOf('/') + 1); // avoid NodeJS path to keep browser webpack small
 		const title = localize('compareChangesTitle', '{0}: Current Changes ⟷ Incoming Changes', fileName);
 		const mergeConflictConfig = vscode.workspace.getConfiguration('merge-conflict');
 		const openToTheSide = mergeConflictConfig.get<string>('diffViewPosition');
@@ -365,4 +365,4 @@ export default class CommandHandler implements vscode.Disposable {
 			conflict: fallback()
 		};
 	}
-}
\ No newline at end of file
+}
diff --git a/extensions/merge-conflict/src/extension.ts b/extensions/merge-conflict/src/mergeConflictMain.ts
similarity index 100%
rename from extensions/merge-conflict/src/extension.ts
rename to extensions/merge-conflict/src/mergeConflictMain.ts
diff --git a/resources/serverless/code-web.js b/resources/serverless/code-web.js
index 2e69b9373b6..d4314c5c3f0 100644
--- a/resources/serverless/code-web.js
+++ b/resources/serverless/code-web.js
@@ -122,7 +122,8 @@ async function initialize() {
 				packageJSON.extensionKind = ['web']; // enable for Web
 				staticExtensions.push({
 					packageJSON,
-					extensionLocation: { scheme: SCHEME, authority: AUTHORITY, path: `/static-extension/${extensionFolder}` }
+					extensionLocation: { scheme: SCHEME, authority: AUTHORITY, path: `/static-extension/${extensionFolder}` },
+					isBuiltin: true
 				});
 			} catch (e) {
 				console.log(e);
diff --git a/src/vs/workbench/services/extensions/common/staticExtensions.ts b/src/vs/workbench/services/extensions/common/staticExtensions.ts
index 6de07f59264..2c8631126a6 100644
--- a/src/vs/workbench/services/extensions/common/staticExtensions.ts
+++ b/src/vs/workbench/services/extensions/common/staticExtensions.ts
@@ -27,6 +27,7 @@ export class StaticExtensionsService implements IStaticExtensionsService {
 		this._descriptions = staticExtensions.map(data => <IExtensionDescription>{
 			identifier: new ExtensionIdentifier(`${data.packageJSON.publisher}.${data.packageJSON.name}`),
 			extensionLocation: data.extensionLocation,
+			isBuiltin: !!data.isBuiltin,
 			...data.packageJSON,
 		});
 	}
diff --git a/src/vs/workbench/workbench.web.api.ts b/src/vs/workbench/workbench.web.api.ts
index 905dbb195c8..3a9b9113d12 100644
--- a/src/vs/workbench/workbench.web.api.ts
+++ b/src/vs/workbench/workbench.web.api.ts
@@ -25,6 +25,7 @@ interface IResourceUriProvider {
 interface IStaticExtension {
 	packageJSON: IExtensionManifest;
 	extensionLocation: URI;
+	isBuiltin?: boolean;
 }
 
 interface ICommontTelemetryPropertiesResolver {