Using HTTP Headers to Serve Styles →
Eric’s proposal is quite ingenious, although I see potential pitfalls.
At the ToonPrint development server, I have implemented an approach that’s a little more subtle, although it’s also easier to miss: based on the current domain, if it matches that of the development server, the <title/>
will have “DEV — ” written at the beginning. This also has the added ability of being easy to spot in a multiple-tab browser window.