backdrop_requirements_severity in includes/install.inc

Extracts the highest severity from the requirements array.

file_requirements in modules/file/file.install

Implements hook_requirements().

image_requirements in modules/image/image.install

Implements hook_requirements() to check the PHP GD Library.

_system_check_db_utf8mb4_requirements in modules/system/system.install

Checks whether the requirements for multi-byte UTF-8 support are met.

system_requirements in modules/system/system.install

Implements hook_requirements().

theme_status_report in modules/system/system.theme.inc

Returns HTML for the status report.

unicode_requirements in includes/unicode.inc

Returns Unicode library status and errors.

update_prepare_bootstrap in includes/update.inc

Performs extra steps required to bootstrap when using a Drupal 7 database.