6 files declare their use of ElementNotFoundException in Zircon Profile 8

Element.php in vendor/behat/mink/src/Element/Element.php

ElementNotFoundExceptionTest.php in vendor/behat/mink/tests/Exception/ElementNotFoundExceptionTest.php

NodeElement.php in vendor/behat/mink/src/Element/NodeElement.php

TraversableElement.php in vendor/behat/mink/src/Element/TraversableElement.php

WebAssert.php in vendor/behat/mink/src/WebAssert.php

WebAssert.php in core/modules/simpletest/src/WebAssert.php

Contains \Drupal\simpletest\WebAssert.