Given our research into what had to change on Talos, we knew we would be making some drastic changes. However, all historical changes to Talos at Mozilla had always suffered from a fear of “breaking the numbers.” The many pieces of Talos were constructed over the years by well-intentioned contributors whose additions made sense at the time, but without documentation or oversight into the direction of the tool chain, it had become a patchwork of code that was not easy to test, modify, or understand.