TYPO3 Core

When defining the uid as label in a tables TCA, BackendUtiltiy->getRecordTitle() might return the uid as integer (I assume, this also depends on the DBMS). This can easily be verified by calling getRecordTitle for the tx_styleguide_elements_rte:

BackendUtility::getRecordTitle('tx_styleguide_elements_rte', BackendUtility::getRecord('tx_styleguide_elements_rte', $uid));