[jarofgreen]

I don't know how much you'd be able to get just from looking at a code base. Most codebases suck in some way, and it's easy to read code and judge - but what is more important is how it's dealt with. eg How good is the CI? What is the team attitude to technical debt? You won't get that from reading the code base.

How about this instead? Ask to briefly shadow some of the team as they do their normal work. You will hopefully get a much more real impression of what working there is like.

I once had an interview last several hours, and in the middle they sat me down with one of the existing workers for a 45 mins chat. The guy talked about watching movies on shift - it was an honest chat.

ps. I work for an employer where almost all our code is open source, so we would find this an easy question :-)