1. Have a checkout of the 6.0 branch of Creator's repository:

   git clone -b 6.0 --depth 1 git://code.qt.io/qt-creator/qt-creator.git
   

   No submodules needed. This is the last branch which still had a .pro file.

2. Open the project qtcreator.pro from this repository in Creator and configure it.
   I used a kit with my self-built Qt 6.6.0.
3. Open the file crashhandlersetup.h.
   You can use the Locator: p crashhandlersetup.h
4. Look at the Projects view near that file:
   
   It's inconsistent. Why is "../tools/qtcreatorcrashhandler" on three levels for the header file but just one node for the source file?

Found by Squish test tst_openqt_creator.