Browser Security From Google
The Browser Security Handbook (BSH) from search engine company Google has been published under free license.
The handbook takes an in-depth look at the individual features of Internet Explorer 6 and 7, Opera, Apple Safari as well as Google's own Chrome. Versions 22.214.171.124 and 3.0.3 and Google's Linux-based browser, mobile SDK Android, also come under scrutiny.
Responsible for the project is Google's Michael Zalewski, who also worked on Chrome, Ratproxy and numerous other web security tools. On the BSH, he had the help of nine other developers.
The Handbook presently exists as Wiki entries on a Google project page and is licensed under the very liberal Creative Commons License that allows the distribution and modification, provided the original author is mentioned.
A complimentary tarball with browser test cases under the Apache License 2.0 is also available.