Is there a way to search Drupal's and contrib modules configuration settings?
Useful fact: drush vget abc lists all variables with 'abc' in their name. So if you are looking for settings related to css, drush vget css might provide you with a clue. Likewise you can use the name of a module in your search to see all the settings from that module.

Some modules have complex settings that are stored in separate database tables. In that case I recommend using a tool such as SQLyog that has a search facility which will scan an entire database, or just specific tables, for a given input string.