The exam environment usually provides whatever online help is provided with the products available from the environment (ex: Linux man pages) and also the product documentation in HTML or PDF format, as you would see in the customer portal (http://access.redhat.com/documentation). The exam instructions tell you where to find the product documentaion.
And that's all. No access to google, stack overflow, Red Hat Developers, etc.
I wrote today EX288 exam and the interface is very bad. As it is running in browser, most of shortcuts will not work and it is too slow for interaction.
THey provided offline documentation, but it will take lots of time to load the page itself and no search in the documentation.
I felt lot of ambiguity in questions.