[ManlyBread]

On my past job I was dealing with something like this and in my opinion source files aren't the best choice for a place to contain such information. To me having a quick reference to an internal documentation is the best: it's just a one line on the screen and when you need to update the information you have a centralized place to do so. If you have programmers that actually give a damn said programmers can learn ins and outs of the domain more easily this way, not to mention that this knowledge can serve non-programmers as well (for example help your support team in solving the issue without engaging the developers of giving your manager visibility into the internals of your work).