When a script or function is called with run(./relative/path/script) the working directory is changed to the ./relative/path. This means pwd it can be used to specify absolute paths:

run(./libs/example_toolbox/load_toolbox)

Which contains :

addpath([pwd, '/function']);

Now The path will contain C:/ ... /libs/example_toolbox/function

As shown in the example this is useful for toolboxes etc which could be distributed with a top level script which adds the toolbox functions on to the path.