Docshell is the second iteration of what originally started out as WebShell. At the moment, the transition from WebShell to DocShell is not fully completed, but the long-term goal is to remove WebShell and switch over entirely to DocShell.
- Original WebShell project page (has good background information, including design of WebShell).
- nsWebBrowser project page (outlines the design of nsWebBrowser and DocShell).
- Overview of a URI load up though dispatch to a content handler.
- Overview of a URI load in general (more bird's-eye view).
- Overview of how Downloads work.
- DocShell Wiki.