TYPO3 Core

Expected goal

$contentSchemaDefinition = (new SomeService)->getSchemaDefinition('tt_content');
$fileReferenceSchemaDefinition = (new SomeService)->getSchemaDefinition('sys_file_reference');
var_dump($contentSchemaDefinition->getProperty('media')->getRelations());
var_dump($fileReferenceSchemaDefinition->getProperty('uid_foreign')->getRelations());

might output something like

# relations for tt_content.media
+ ActiveRelation: schemaName "sys_file_reference" 

# relations for sys_file_reference.uid_foreign
+ PassiveRelation: schemaName "tt_content", propertyName: "image" 
+ PassiveRelation: schemaName "tt_content", propertyName: "media" 
+ PassiveRelation: schemaName "tt_content", propertyName: "assets" 

Currently the "opposite usage" for relations is not explicitly known. In order to enhance look ups this information should be cached along with the plain schema definition (e.g. TCA).