list_themes in includes/theme.inc

Returns a list of all currently available themes.

module_disable in includes/module.inc

Disables a given set of modules.

module_enable in includes/module.inc

Enables or installs a given list of modules.

_system_update_bootstrap_status in modules/system/system.module

Refresh bootstrap column in the system table.

system_update_files_database in modules/system/system.module

Updates the records in the system table based on the files array.

update_module_enable in includes/update.inc

Helper function to install a new module in Backdrop 1.x via hook_update_N().