As you can see, I am using DokuWiki. It is a fabulous tool in the sense that everything is in a file, and no dependence on MySQL et al.
But it is quite big now and no big code is easy to learn — which means I have to spend time to understand it! So my journey starts here.
Copied from http://wiki.splitbrain.org/wiki:devel:dirlayout
dokuwiki – DokuWiki root directory - maybe you named it differently_darcs – darcs metadata, you have this only if you’re using a darcs checkout_test – contains the Unit Test Suiteconf – Configuration data is stored heredata – All data that is written by DokuWiki is stored here, the changelog is placed here, tooattic – old page revisions are stored here, it contains namespace directoriescache – DokuWiki creates cachefiles to speed things up - cachefiles have md5 filenames and are stored inside 16 directories here, sorted by their first letter (0-f)locks – This directory is used to create temporary locks (not pagelocks)media – here are all image files stored, it contains namespace directoriesmeta – not used yet but will store meta data for pages, it contains namespace directoriespages – here are the raw pages stored, it contains namespace directoriesinc – contains PHP libs – the core of DokuWikiauth – authentication backendsgeshi – The GeShi syntax highlighting language definitionslang – DokuWiki’s translation filesmagpie – The magpie RSS parserparser – DokuWiki’s wiki:parser systemlib – Files that get called externally (from your browser)exe – externally access PHP files (for AJAX)images – Images filesinterwiki – wiki:interwiki iconssmileys – wiki:smiley iconstoolbar – quickbutton iconsplugins – Plugins are stored hereacl – The ACL plugininfo – The Info pluginconfig – The Configuration Settings pluginplugin – The Plugin Manageruser – The User Managerscripts – Javascript filesstyles – CSS style filestpl – Templatesdefault – The default template