11 string references to 'Source' in Openlayers 7.3

Autopopup::optionsForm in src/Plugin/Component/Autopopup/Autopopup.php

@TODO What is this return? If it is the form, why is form by reference?

Cluster::optionsForm in src/Plugin/Source/Cluster/Cluster.php

@TODO What is this return? If it is the form, why is form by reference?

ImageVector::optionsForm in src/Plugin/Source/ImageVector/ImageVector.php

@TODO What is this return? If it is the form, why is form by reference?

openlayers.services.yml in ./openlayers.services.yml

openlayers.services.yml

openlayers_layer_form_type in modules/openlayers_ui/src/Plugin/export_ui/OpenlayersLayers.inc

Layer type config form handler.

openlayers_source_form_options in modules/openlayers_ui/src/Plugin/export_ui/OpenlayersSources.inc

Source options config form handler.

openlayers_source_form_options_submit in modules/openlayers_ui/src/Plugin/export_ui/OpenlayersSources.inc

Source options config form submit handler.

openlayers_source_form_options_validate in modules/openlayers_ui/src/Plugin/export_ui/OpenlayersSources.inc

Source options config form validation handler.

openlayers_source_form_type in modules/openlayers_ui/src/Plugin/export_ui/OpenlayersSources.inc

Source type config form handler.

Snap::optionsForm in src/Plugin/Interaction/Snap/Snap.php

@TODO What is this return? If it is the form, why is form by reference?

ZoomToSource::optionsForm in src/Plugin/Component/ZoomToSource/ZoomToSource.php

@TODO What is this return? If it is the form, why is form by reference?