src/vs/workbench/common/editor/editorGroupModel.ts/isSerializedEditorGroupModel
export function isSerializedEditorGroupModel(group?: unknown): group is ISerializedEditorGroupModel {
	const candidate = group as ISerializedEditorGroupModel | undefined;

	return !!(candidate && typeof candidate === 'object' && Array.isArray(candidate.editors) && Array.isArray(candidate.mru));
}