There's a bit of documentation in the source file (lib/config.lib.php). There was a doc file for the config in AdminPanel, but either it never got moved over or it got stripped cause zanix doesn't want a wildgrow of docs but all in the wiki, or some other reason I forgot.
config documentation wrote:$Id: config.txt 96 2006-08-22 15:07:24Z pleegwat $
This is the current functionality of the config class.
There are two classes of form types: Option blocks for layout, and the actual
options. Items of the page, pageframe, and pagehide class contain option blocks.
Items of the blockframe or blockhide class contain options.
Menu bar items:
page, pageframe, pagehide, blockframe, blockhide:
A page of options that gets selected with javascript
link:
An external link to be opened in the same window
newlink:
An external link to be opened in a new window
In the URLs for these links, %roster% is substituted for the roster
base url, and %addon% is substituted for the addon's dbname.
Options blocks:
page{n:
n collumns of options blocks
pageframe{n
n collumns of options blocks in a border
pagehide{n
n collumns of options blocks in a border, with a show/hide option
blockframe
A list of options in a border
blockhide
A list of options in a border, witha show/hide option
function{name
Calls the function called name with no parameters to produce the HTML
for the page. If this is a tab (directly linked from the switch menu on
the left side) it is put outside the main form so you can put forms in it.
Options:
text{n|m
A text box m characters wide, maximum of n characters input
radio{op1^val1|op2^val2|op3^val3...
A list of radio buttons with labels op1, op2, op3,... which produce
values val1, val2, val3,... Labels are literal, not localization keys.
select{op1^val1|op2^val2|op3^val3...
A a dropdown box with options op1, op2, op3,... which produce
values val1, val2, val3,... Labels are literal, not localization keys.
function{name
Calls the function called name with the option record as parameter to
produce the HTML for the option.
display
Displays the option's setting.
config.func.php:
Both function types call functions that are defined in a file called
'config.func.php' in your addon's directory. If this file sets
$addon_hastopbox to true it should define a function topbox(). The html
returned by this function will be put above the options in the middle
collumn.
The only change since I last updated that file is that the config.func.php is now in the admin/ dir.