Unit tests are failing - Your XML configuration validates against a deprecated schema.

FWIW: tried this in a ddev container where I have just installed this module:

roderik@lupus-decoupled-web:/var/www/html$ vendor/bin/phpunit  web/modules/contrib/ohdear_integration/tests/src/Functional/OhdearIntegrationEndpointTest.php

PHPUnit 9.6.15 by Sebastian Bergmann and contributors.

Testing Drupal\Tests\ohdear_integration\Functional\OhdearIntegrationEndpointTest
.                                                                   1 / 1 (100%)

Time: 00:03.885, Memory: 4.00 MB

OK (1 test, 15 assertions)

Remaining self deprecation notices (3)

  2x: watchdog_exception() is deprecated in drupal:10.1.0 and is removed from drupal:11.0.0. Use \Drupal\Core\Utility\Error::logException() instead. See https://www.drupal.org/node/2932520
    2x in OhdearIntegrationEndpointTest::testApiResponseData from Drupal\Tests\ohdear_integration\Functional

  1x: format_size() is deprecated in drupal:10.2.0 and is removed from drupal:11.0.0. Use \Drupal\Core\StringTranslation\ByteSizeMarkup::create($size, $langcode) instead. See https://www.drupal.org/node/2999981
    1x in OhdearIntegrationEndpointTest::testApiResponseData from Drupal\Tests\ohdear_integration\Functional

The deprecation notices are not failures.

Guessing: is it maybe your local(ly copied some time ago) phpunit.xml that is older and needs updating?

No more deprecations are reported as per phpstan pipeline: https://git.drupalcode.org/project/ohdear_integration/-/jobs/2519000 for both 1.x and 2.x branch
I guess we can close this one.

Tests are now green but they will need to be revised and take caching into account more.

Automatically closed - issue fixed for 2 weeks with no activity.