Cool idea. Have we considered looking at the gitignore and gitattributes files as well? You can often figure out the IDE and other tools someone is using by looking at these.

As a counterpoint: I often see technology-specific gitignore files, created from a template, that attempt to cover all commonly used tools. Can't really tell what is actually used from that.

In my experience .gitignore files are often overloaded, so would provide false positives.

indeed never thought of that but could be an interesting data point