src/vs/platform/backup/electron-main/backupMainService.ts/BackupMainService/storeWorkspacesMetadata
class BackupMainService:	private storeWorkspacesMetadata(): void {
		const serializedBackupWorkspaces: ISerializedBackupWorkspaces = {
			workspaces: this.workspaces.map(({ workspace, remoteAuthority }) => {
				const serializedWorkspaceBackupInfo: ISerializedWorkspaceBackupInfo = {
					id: workspace.id,
					configURIPath: workspace.configPath.toString()
				};

				if (remoteAuthority) {
					serializedWorkspaceBackupInfo.remoteAuthority = remoteAuthority;
				}

				return serializedWorkspaceBackupInfo;
			}),
			folders: this.folders.map(({ folderUri, remoteAuthority }) => {
				const serializedFolderBackupInfo: ISerializedFolderBackupInfo =
				{
					folderUri: folderUri.toString()
				};

				if (remoteAuthority) {
					serializedFolderBackupInfo.remoteAuthority = remoteAuthority;
				}

				return serializedFolderBackupInfo;
			}),
			emptyWindows: this.emptyWindows.map(({ backupFolder, remoteAuthority }) => {
				const serializedEmptyWindowBackupInfo: ISerializedEmptyWindowBackupInfo = {
					backupFolder
				};

				if (remoteAuthority) {
					serializedEmptyWindowBackupInfo.remoteAuthority = remoteAuthority;
				}

				return serializedEmptyWindowBackupInfo;
			})
		};

		this.stateMainService.setItem(BackupMainService.backupWorkspacesMetadataStorageKey, serializedBackupWorkspaces);
	}