Here is a quick step by step guide for the mac users out there who would like to have a Mumble overlay that shows who's talking in mumble while you are in game.
Step 1: Navigate to the "Utilities" folder which is located in your "Applications" folder.
Step 2: Open "AppleScript Editor"
Step 3: Paste "do shell script "/Applications/Mumble.app/Contents/Overlay/mumble-overlay /" into the editor.
Step 4: Find your Urban Terror application, highlight it, then press +i (command i) on your keyboard to "Get Info". A window should appear with the path to the application.
Step 5: Copy the path to the file and paste it into the AppleScript Editor. Then, press "/" once after the path to the file. Then, copy and paste the application name after the "/". Then, put a quote at the end. It should look similar to this. Note that you're path to the game may be different than the one in the screenshot.
Step 6: Press "Compile" to make sure there aren't any errors. If there are it's likely there is a typo in you're path to the game. After a successful compile the text will turn from pink, to blue and black. Now save your script as an application and check off the "Run only" box.
Step 7: Go into your Mumble preferences and check off the "Advanced" box in the top right corner. Now go to the "Overlay" panel, enable the overlay, and set the text colors and font to the way you want.
Now if you have done everything correctly, the application you saved should open Urban Terror with an overlay!