install_main in ./install.php
The Drupal installation happens in a series of steps. We begin by verifying that the current environment meets our minimum requirements. We then go on to verify that settings.php is properly configured. From there we connect to the configured database…
module_disable in includes/module.inc
Disable a given set of modules.
module_enable in includes/module.inc
Enable a given list of modules.
module_exists in includes/module.inc
Determine whether a given module exists.
module_implements in includes/module.inc
Determine which modules are implementing a hook.
module_load_all_includes in includes/module.inc
Load an include file for each of the modules that have been enabled in the system table.
system_install in modules/system/system.install
Implementation of hook_install().
system_modules_submit in modules/system/system.admin.inc
Submit callback; handles modules form submission.
system_requirements in modules/system/system.install
Implementation of hook_requirements().
system_update_6027 in modules/system/system.install
Add block cache.
update.php in ./update.php
Administrative page for handling updates from one Drupal version to another.
_theme_process_registry in includes/theme.inc
Process a single invocation of the theme hook. $type will be one of 'module', 'theme_engine', 'base_theme_engine', 'theme', or 'base_theme' and it tells us some important information.