src/vs/workbench/contrib/tasks/browser/abstractTaskService.ts/AbstractTaskService/openConfig
class AbstractTaskService:	public async openConfig(task: CustomTask | ConfiguringTask | undefined): Promise<boolean> {
		let resource: URI | undefined;
		if (task) {
			resource = this._getResourceForTask(task);
		} else {
			resource = (this._workspaceFolders && (this._workspaceFolders.length > 0)) ? this._workspaceFolders[0].toResource('.vscode/tasks.json') : undefined;
		}
		return this._openEditorAtTask(resource, task ? task._label : undefined, task ? task._source.config.index : -1);
	}