How do you build and test a new web browser when nobody in the world -- outside of the tiny development team -- is allowed to know of its existence? Very carefully, according to Safari engineer Don Melton, who detailed some of the finer points of covert browser building on his personal blog.
Everything from hiring the team to testing the browser online was done in complete secrecy. Prospective Safari team members didn't even know what they were interviewing for or what they would be working on, and once they were brought on board, they swore an oath of loyalty. But while the personnel acted like walking vaults of top-secret information, actually using Safari on the public web presented an entirely different set of challenges.
Namely, the user agent strings that tell each server what browser is being used, and where the individual visiting the site is located. So to keep Safari from showing up on server logs across the web during the testing phase, the entire team had to hide that information while browsing from Apple HQ. But in order to ensure that the user agent string was enabled in time for the launch of the product, the team set the real string to enable automatically on January 7, 2003, just days before Steve Jobs revealed it to the public for the first time at Macworld Expo. If you're interested in reading more, check out Melton's full account of the process.