When you build an embassy, you get to see the capital of the civilization that you investigated (just like the screen you see when you double click on one of your cities). You'll see various things such as Culture, Government, Resources, Gold, and City Found Date in the very top of the screen. You'll see what tiles they are working from the middle portion of the screen. In the bottom third, you'll see what luxuries they have, how many, what improvements they have, food (and food per turn), shields (and shields per turn).
The place where WackenOpenAir found out the slider info was in the commerce section: it'll show you how his commerce is divided up: you'll see a % number next to a gold chest, a science beaker, and a happy face. The % is the % of his income that is devoted to taxes, science, and luxury tax, respectively (as changed by the slider on the F1 screen). Hope this helps.
