I thought this about Eagle's[1] project storage switching to XML; I figured it would allow us to store projects and libraries in git and easily branch / merge changes etc.

It was a nightmare. XML does not work well in git.[2] I even thought I could resolve some of the issues by sorting elements so they'd be in a consistent order, but none of the elements had guuids or anything to allow me to do that.

1: http://dangerousprototypes.com/blog/2010/10/14/eagle-open-xm...

2: https://blog.joepairman.com/2016/11/26/xml-in-git-mercurial-...