Since AUC TeX is so highly customizable, it makes sense that it is able to customize itself. The automatic customization consists of scanning TeX files and extracting symbols, environments, and things like that.
The automatic customization is done on three different levels. The global level is the level shared by all users at your site, and consists of scanning the standard TeX style files, and any extra styles added locally for all users on the site. The private level deals with those style files you have written for your own use, and use in different documents. You may have a `~/lib/TeX/' directory where you store useful style files for your own use. The local level is for a specific directory, and deals with writing customization for the files for your normal TeX documents.
If compared with the environment variable TEXINPUTS, the
global level corresponds to the directories built into TeX. The
private level corresponds to the directories you add yourself, except for
`.', which is the local level.
By default AUC TeX will search for customization files in all the
global, private, and local style directories, but you can also set the
path directly. This is useful if you for example want to add another
person's style hooks to your path. Please note that all matching files
found in TeX-style-path are loaded, and all hooks defined in the
files will be executed.
By default, when AUC TeX searches a directory for files, it will recursively search through subdirectories.
By default, AUC TeX will ignore files name `.', `..', `SCCS', `RCS', and `CVS'.
These files or directories will not be considered when searching for TeX files in a directory.