backdrop_autoload in includes/bootstrap.inc

Confirms that a class is available.

backdrop_find_backends in includes/bootstrap.inc

This is a wrapper for silkscreen_find_backends(), in case someone happened to call it.

backdrop_load_backends in includes/bootstrap.inc

Find and load all files for the requested backend type.

config_get_config_storage_handlers in includes/config.inc

Collect a list of classes for each "type" (e.g., db or file).

Database::loadDriverFile in includes/database/database.inc

Load a file for the database that might hold a class.

Database::openConnection in includes/database/database.inc

Opens a connection to the server specified by the given key and target.