Is there no preferenced codestyle/formatting?
I searched in the forum and the wiki and the only thing I found is from 2011 https://forum.freecadweb.org/viewtopic.php?f=10&t=837
I expected at least one hit when searching “codestyle”, “style guide” or something like “clang-format”…
At which point there’s some style enforced, during the pull request?
Generally I tend to try applying the same style as the file(s) I’m modifying. 
Each workbench has it’s variations, for example:
FEM workbench https://github.com/FreeCAD/FreeCAD/blob/master/src/Mod/Fem/coding_conventions.md
Draft and Arch https://github.com/FreeCAD/FreeCAD/blob/master/src/Mod/Draft/coding_conventions.md
It comes up from time to time, but the basic preference here seems to be to not worry too much about it, and to let devs focus on developing — we’ve probably all seen in other projects how discussions about style turn into bikeshedding pretty quickly. That said, our C++ more or less follows the Qt style guide here: https://wiki.qt.io/Qt_Coding_Style