Years ago I wrote some VBA that exports all the VBA in an Excel file. I ran this script manually from time to time so I could add my code to version control. Excel should make it easier to separate the code from the data. For the former you probably want the entire commit history, for the latter you usually only want the current state.
When I was doing a lot of VBA work like this, I used an OSS tool that would export all of the code and check it into SVN. I can't remember the name of it for the life of me, though, but it's probably hiding on a drive somewhere.
I work in a lab where there are lots of excel sheets floating around. I went one step further - when I save an xltm (an excel template), the code is exported and then a bash script automatically uploads it into my git repo. The VBA asks for a commit message and then all the rest is automatic. It's worked pretty well, all things considered.
I once wrote an MSBuild script that decompiled a workbook into XML and VBA code. It used a CLI tool I wrote that opened the workbook using VSTO to access the VBA objects.
I never finished it, though. I only spent enough time on it to realize that it was going to be too big of a project to make it worth it.
So now I just rename the workbook to a zip file, extract it, and check that into git. Only drawback is that the VBA macros are in an OLE container. But I stay away from VBA, so it's not that big of a deal for me.
