src/vs/platform/backup/electron-main/backupMainService.ts/BackupMainService/registerEmptyWindowBackup
class BackupMainService:	registerEmptyWindowBackup(emptyWindowInfo: IEmptyWindowBackupInfo): string {
		if (!this.emptyWindows.some(emptyWindow => !!emptyWindow.backupFolder && this.backupPathComparer.isEqual(emptyWindow.backupFolder, emptyWindowInfo.backupFolder))) {
			this.emptyWindows.push(emptyWindowInfo);
			this.storeWorkspacesMetadata();
		}

		return join(this.backupHome, emptyWindowInfo.backupFolder);
	}