Pandoc has a publicly accessible git repository at github. To get a local copy of the source:
git clone git://github.com/jgm/pandoc.git
Note: after cloning the repository (and in the future after pulling from it), you should do
git submodule update --init
to pull in changes to the templates. You can automate this by creating a file .git/hooks/post-merge with the contents:
#!/bin/sh
git submodule update --init
and making it executable:
chmod +x .git/hooks/post-merge