ivan tkachenko authored Dec 01, 2021 and Nate Graham committed Dec 02, 2021

It is an implementation detail, and was never meant to be a public API.
While there are no traces of its usage (outside of the Heading
component itself) in the whole KDE infrastructure, we still can not
remove it until the next major version, as it would technically be a
breaking change for 3rd-party libraries.