[TASK] Implement placeholders

Resolves: #58481
Releases: 6.2
Change-Id: I0482f2a93ba3aad5465a26e3d77728337b1ca8b8
Reviewed-on: https://review.typo3.org/29887
Reviewed-by: Nico de Haen
Tested-by: Nico de Haen