admin/

Contains the admin interface.

admin/errors/

Errors are logged in XML format here, which could help you resolve issues that occur. This folder might move to data/errors/ at some point, so that errors are logged on a per-site basis.

admin/sites/

Each site has a folder of its own in here, (sites are identified by number, the initial install is 1), and it's the best place to add custom admin pages, which can be accessed at admin/custom/[page].

sites.ini

This is a list of install locations, which is handy for maintenance scripts.

admin/ws/

Most day-to-day database and filesystem interaction occurs through the files in this folder. Usually the functionality in the PHP files occurs through PHP, but most functions can also be called via AJAX.

The skeleton of each file was generated by a tool called RapidDev (it's not available on the internet - yet), which explains why they look as twisted as they do. The WSDL files don't do anything by themselves, but if you're clever you can apply an XML stylesheet to them and do anything you like. One day I'll get around to explaining this further.

common/

Contains files relating to all installed sites. This folder is the core of the CMS. If multiple sites are running off one install, this folder is symlinked to each one.

data/

Each site has its own data directory, this is where you store files specific to each site.

header.inc, footer.inc

Called at the start and end of each page, these files allow you to add custom features to your website. They should, at the very least, call doPageHeader() and doPageFooter().

navi.inc

Implements a simple list which you can output in header.inc. The list is editable through the Navigation link on the admin page.

phpheader.inc

This is the very first file read for every page on your website. It sets all the appropriate settings, before anything else occurs.

users.db

This is the database of users and session information. It's possible to symlink this file across sites, to keep all the same users (and with the right cookie setup, one login across multiple subdomains).

install/

Contains all the install system. We leave it all behind after installation for possible future maintenance.