Absolutely. I spent forever reverse engineering the format to write a Python parser (https://github.com/microsoft/xcodeproj). It covers the projects I need it to (one in particular is very complex, probably in the top 100 most complex ones out there - I'm sure you can figure out which from my profile). However, there are plenty of areas I had to guess. And this is just for reading, no writing support has been added at this point.