:mod:`sphinx.ext.viewcode` -- Add links to highlighted source code
This extension looks at your Python object descriptions (.. class::, .. function:: etc.) and tries to find the source files where the objects are contained. When found, a separate HTML page will be output for each module with a highlighted version of the source code, and a link will be added to all object descriptions that leads to the source code of the described object. A link back from the source to the description will also be inserted.
There are currently no configuration values for this extension; you just need to add 'sphinx.ext.viewcode' to your :confval:`extensions` value for it to work.