src/vs/platform/backup/electron-main/backupMainService.ts/BackupMainService/registerWorkspaceBackup
class BackupMainService:	registerWorkspaceBackup(workspaceInfo: IWorkspaceBackupInfo, migrateFrom?: string): string | Promise<string> {
		if (!this.workspaces.some(workspace => workspaceInfo.workspace.id === workspace.workspace.id)) {
			this.workspaces.push(workspaceInfo);
			this.storeWorkspacesMetadata();
		}

		const backupPath = join(this.backupHome, workspaceInfo.workspace.id);

		if (migrateFrom) {
			return this.moveBackupFolder(backupPath, migrateFrom).then(() => backupPath);
		}

		return backupPath;
	}