Useful tools and tricks for contributing to Servo:

DXR - source code index, updated regularly. Add a Firefox search keyword to use it more efficiently (for example, sxr ScriptTask for text search, sxrf file_loader.rs for filename).

Assuming you are in the root directory of the Servo project,

    RUST_SRC=./src/compiler/rust/src
    ctags-exuberant -e -f TAGS.emacs --languages=rust --options=$RUST_SRC/etc/ctags.rust -R src

will build the tags table in TAGS.emacs (takes around 3s)

You can then jump to the definition of any function or struct or enum by using M-. (Alt + .)

See the Emacs support page on the Rust wiki