But that's not what's being asked. Consider a Keyword test that looks like this:
Now, someone comes in and changes it to add a new step
Someone then wants to compare the two tests and see what changed. Right now, any tool out there will look at the XML strcuture of the tcKDT file and show the differences there. That's fine if you can read and parse XML. But what would be COOL is some sort of keyword test comparison tool which would highlight the specific changes as they show up in TestComplete without having to parse the XML.
In these examples, it's not the project or the project suite that has changed, but the keyword test. Comparing the MDS or PJS file doesn't really work in this case. And, for that matter, the idea is to avoid having to look at the XML but to look at something more visually analogous to what shows up in TestComplete. Perhaps the end result of the comparison tool would look something like this, highlighting where the differences are, green for add, red for removed sort of thing: