If you are an admin and you have found yourself wondering what all is running under the hood on my site, there is a tool for you. In the Site Admin tools under Development is a view that can show you Third party libraries that are installed on the build at Open LMS. Development -> Third party libraries (nicely named!)
It isn't everything in our architecture, but it is a good view of all the supporting technology that the site has access to in order to run.
This combined with some other views like Server -> Environment and Server -> PhP info can give you a robust view of the tools and versions in use on the platform. It can't answer all the questions you might have, but it sure gives you a lot of information.
Check it out sometime!