REGIONS_VISIBLE

BlockController::getVisibleRegionNames in core/modules/block/src/Controller/BlockController.php

Returns the human-readable list of regions keyed by machine name.

BlockForm::form in core/modules/block/src/BlockForm.php

Gets the actual form array to be built.

BlockForm::themeSwitch in core/modules/block/src/BlockForm.php

Handles switching the available regions based on the selected theme.

BlockListBuilder::buildBlocksForm in core/modules/block/src/BlockListBuilder.php

Builds the main "Blocks" portion of the form.

BlockPlaceTest::testPlacingBlocksAdmin in core/modules/block_place/tests/src/Functional/BlockPlaceTest.php

Tests placing blocks as an admin.

... See full list