Crawler's personalities are often configured by means of configuration files.
There is no hard rule that dictates what format these configuration files should use. They could be text files, INI files, XML-based files,...
Because INI files are easy to understand for end-users, most of the pre-made personalities use INI-based configuration files.
For more popular personalities, GUI-driven configuration tools might be provided, but in many cases, the GUI-development will lag behind on the functionality, in which case the next easiest method to (re)configure a Crawler personality is to edit one or more configuration files.