src/vs/workbench/services/userDataProfile/browser/userDataProfileImportExportService.ts/UserDataProfileImportExportService/registerProfileContentHandler
class UserDataProfileImportExportService:	registerProfileContentHandler(id: string, profileContentHandler: IUserDataProfileContentHandler): IDisposable {
		if (this.profileContentHandlers.has(id)) {
			throw new Error(`Profile content handler with id '${id}' already registered.`);
		}
		this.profileContentHandlers.set(id, profileContentHandler);
		return toDisposable(() => this.unregisterProfileContentHandler(id));
	}