It leaks KToolBar from KXmlGui into the public API. I did not find any code using it
5.65 isn't released yet, you can use 5.65 as deprecation version here.
I started a kdesrc-build with the method removed, and found that KFileDialog::toolBar (in kdelibs4support) uses it, so it needs a matching #if in case EXCLUDE_DEPRECATED_BEFORE_AND_AT.
This patch itself is still correct though, of course.