This document is meant to provide web application developers, browser engineers, and information security researchers with a one-stop reference to key security properties of contemporary web browsers. Insufficient understanding of these often poorly-documented characteristics is a major contributing factor to the prevalence of several classes of security vulnerabilities.
Although all browsers implement roughly the same set of baseline features, there is relatively little standardization – or conformance to standards – when it comes to many of the less apparent implementation details. Furthermore, vendors routinely introduce proprietary tweaks or improvements that may interfere with existing features in non-obvious ways, and seldom provide a detailed discussion of potential problems.
The document is available here