color_requirements in drupal-6.x/modules/color/color.install

drupal_requirements_severity in drupal-6.x/includes/install.inc

Extract highest severity from requirements array.

system_requirements in drupal-6.x/modules/system/system.install

Implementation of hook_requirements().

theme_status_report in drupal-6.x/modules/system/system.admin.inc

Theme requirements status report.

unicode_requirements in drupal-6.x/includes/unicode.inc

Return Unicode library status and errors.

... See full list