The "fake_block_content" entity type does not exist

It would be a good idea to enable automated tests for bootstrap_layouts. It would help track down the problem to see whether or not this issue appears here. Even if there are no tests running tests will check of it builds successfully.

If I make a completely empty functional test and enable bootstrap_layouts in it, I get this error when running tests:

1) Drupal\Tests\bc_dc\Functional\BcDcFunctionalTest::test
Drupal\Component\Plugin\Exception\PluginNotFoundException: The "block_content_type" entity type does not exist.

The tests pass if I comment-out the following from BootstrapLayoutsPluginManager::__construct():

// Replace the namespaces data.
$namespaces->exchangeArray($ns);