Also known as the Linux Cross-Reference, LXR is a client/server application that helps software developers navigate through large volumes of code. LXR was initially developed with the sole intent of making the Linux source code more accessible for developers, students and interested parties that are unfamiliar with its entire structure. Later on, the LXR project expanded its views by making the system applicable to more generic code bases. The Mozilla web browser is one such code base, as is the FreeBSD operating system.
LXR was built as a client/server application. On the client side LXR makes use of generic web software. This means that anyone with a WWW browser can connect to a server and view the code, so users don't need to install any special applications. On the server side, LXR consists of a indexing tool written in the Perl programming language and a UNIX web server with cgi facilities, like Apache.
The LXR source code has been released under the GNU Copyleft license. Development is supervised by Sourceforge.
Information:
lxr.linux.no
LXR FAQ