src/vs/workbench/services/extensionManagement/browser/webExtensionsScannerService.ts/WebExtensionsScannerService/scanExtensionManifest
class WebExtensionsScannerService:	async scanExtensionManifest(extensionLocation: URI): Promise<IExtensionManifest | null> {
		const packageJSONUri = joinPath(extensionLocation, 'package.json');
		try {
			const content = await this.extensionResourceLoaderService.readExtensionResource(packageJSONUri);
			if (content) {
				return JSON.parse(content);
			}
		} catch (error) {
			this.logService.warn(`Error while fetching package.json from ${packageJSONUri.toString()}`, getErrorMessage(error));
		}
		return null;
	}