"displayClass" missing in template

[SventB]

Bug Report

Prerequisites

• [x] Can you reproduce the problem on TYPO3 v11.5 LTS
• [x] Can you reproduce the problem on TYPO3 v12.4 LTS
• [x] Did you perform a cursory search to see if your bug or enhancement is already reported?

Description

Property "displayClass" is missing for h4: https://github.com/benjaminkott/bootstrap_package/blob/master/Resources/Private/Partials/ContentElements/Header/Header.html#L20