2 calls to _theme_build_registry()

_theme_load_offline_registry in includes/theme.maintenance.inc
Builds the registry when the site needs to bypass any database calls.
_theme_load_registry in includes/theme.inc
Gets the theme_registry cache; if it doesn't exist, builds it.

Buggy or inaccurate documentation? Please file an issue. Need support? Need help programming? Connect with the Drupal community.