ms excel how to transfer customised toolbars

I customise intensively lots of shortcuts, rules, scripts etc on my computer. Starting on a new computer is complicated then, because transfer to new computers and versions is not always easy or even possible.

In older ms excel (office) versions, the customised toolbars were in some file in the preference/startup folder. Now I can still modify toolbars etc in my recent version, but do not find the file it contains. That means that I have to rewrite all the macro's, buttons, shortcuts etc on all the computers I work on. This cannot be meant to be. I must have missed something. Any one know where that file is ?