Part of meta-issue #1518116: [meta] Make Core pass Coder Review
Postponed because of #1326664: Clean up API docs for system module (excluding subdirectories)
Updating for #1299424: Allow one module per directory and move system tests to core/modules/system
As part of #1800046: [META] Add missing type hinting to core docblocks, I created a sub-issue #1800330: Add missing type hinting to System module docblocks to address the addition of missing type hinting to the System module.
Drupal is a registered trademark of Dries Buytaert.