Show variable and array lists

Document the variables and arrays used within Drupal core and available to developers and users through the Drupal interface. This information would be invaluable for people trying to code PHP snippets.

vid, uid, nid, etc, etc. We need to know the variable names and structure of these arrays in order to build php, use functions or develop modules! Much too hard to find this information right now.

It would also help to document the database structure of Drupal core tables.