Location sources / My places
This feature allows you to configure saved locations such as "Home" or "Work" which can then be used by other apps as a convenience feature.
Additionally, apps may recognise when you are at one of these locations and use this to provide context-sensitive features.
This feature has the ability to notify apps when you are at home or work, and where your home and work are. You may not want apps to be able to know this information.
This feature can be enabled even when Google Location History is disabled, so you will need to disable both separately if don't want either.