Specifications for the distribution are maintained in the doc/specs.git repository and published in HTML format on the specs Web site.
Building Locally
Newer specifications like SPF 2.0 are multi-chapter books rendered from Markdown source files using the custom-developed "markdownbook" software. markdownbook is currently used as a submodule of the specs repository.
One can download and build a local copy of the specifications from the repository using the following commands:
$ git clone git://git.proteanos.com/doc/specs.git
$ cd specs
$ git submodule init
$ git submodule update
$ make
This will render HTML versions of the specifications in the source tree. You can view these in a Web browser, e.g.:
$ x-www-browser specs/spf-2.0/index.html