What module is used to create the table of contents in Drupal documentation? I want to create a table of contents for sections of my site like Drupal.org has for their documentation. For example on this page, there is the "Table of Contents" block on the right hand side. What module is used to do this?
That block is the "Book navigation" block implemented by the Book module in book_block_view(), and defined in book_block_info().

The copyright block that appears right after the "Book navigation" block is implemented in drupalorg_handbook.module, which is a custom module used to run Drupal.org, and its sub-domains.