src/vs/platform/extensionManagement/node/extensionManagementService.ts/ExtensionsScanner/setUninstalled
class ExtensionsScanner:	async setUninstalled(...extensions: IExtension[]): Promise<void> {
		const extensionKeys: ExtensionKey[] = extensions.map(e => ExtensionKey.create(e));
		await this.withUninstalledExtensions(uninstalled =>
			extensionKeys.forEach(extensionKey => {
				uninstalled[extensionKey.toString()] = true;
				this.logService.info('Marked extension as uninstalled', extensionKey.toString());
			}));
	}