bootstrap.inc in core/includes/bootstrap.inc
Functions that need to be loaded on every Backdrop request.
drupal.inc in core/includes/drupal.inc
Contains constants and function wrappers for Drupal 7.x compatibility.
hook_requirements in core/modules/system/system.api.php
Check installation requirements and do status reporting.
install_profile_info in core/includes/install.inc
Retrieves information about an installation profile from its .info file.
system_requirements in core/modules/system/system.install
Implements hook_requirements().
update_module_add_to_system in core/includes/update.inc
Adds modules to the system table in a Backdrop core update.
_system_rebuild_module_data in core/modules/system/system.module
Helper function to scan and collect module .info data.
_system_rebuild_theme_data in core/modules/system/system.module
Helper function to scan and collect theme .info data and their engines.