The child records that are created within repeatable sections can have their own unique location information that is stored along with the child record data. There are a variety of use cases where this can be helpful, like collecting feature data at a park. Each child record, feature in the park, can have it's own location captured and stored within that record.
In the repeatable section field popup on the app designer page you will find three location related options. These options are similar to the location options that you can set for an app but used for just the child records captured within the repeatable section.
Location Enabled - This is enabled by default and means that the user will have the option of setting a location for the child records created within this repeatable section. The mobile apps will attempt to use the device's GPS to populate the child record with the location of the device as soon as the child record is created.
Location Required - When enabled this will require the child record to have a location before the child record can be fully saved.
Advanced Geometry Enabled - Enables the lines and polygons feature for the repeatable section.