src/vs/workbench/services/workspaces/browser/workspacesService.ts/BrowserWorkspacesService/createUntitledWorkspace
class BrowserWorkspacesService:	async createUntitledWorkspace(folders?: IWorkspaceFolderCreationData[], remoteAuthority?: string): Promise<IWorkspaceIdentifier> {
		const randomId = (Date.now() + Math.round(Math.random() * 1000)).toString();
		const newUntitledWorkspacePath = joinPath(this.environmentService.untitledWorkspacesHome, `Untitled-${randomId}.${WORKSPACE_EXTENSION}`);

		// Build array of workspace folders to store
		const storedWorkspaceFolder: IStoredWorkspaceFolder[] = [];
		if (folders) {
			for (const folder of folders) {
				storedWorkspaceFolder.push(getStoredWorkspaceFolder(folder.uri, true, folder.name, this.environmentService.untitledWorkspacesHome, !isWindows, this.uriIdentityService.extUri));
			}
		}

		// Store at untitled workspaces location
		const storedWorkspace: IStoredWorkspace = { folders: storedWorkspaceFolder, remoteAuthority };
		await this.fileService.writeFile(newUntitledWorkspacePath, VSBuffer.fromString(JSON.stringify(storedWorkspace, null, '\t')));

		return this.getWorkspaceIdentifier(newUntitledWorkspacePath);
	}