Hello,
in the last few days, for some reason, CI jobs related to the coverage fails with this reason:

04:16:11 Finding coverage difference in ede7dc8b68b63373b38fee56facaccf5b7d62589
04:16:11 $ php -d zend_extension=xdebug.so tests/phpunit/phpunit.php --coverage-clover /tmp/cloverETlRWo --filter '/MediaWikiIntegrationTestCase|MediaWikiTestCaseTrait|DiffHistoryBlobTest/'
04:16:11 PHP Warning:  Failed loading Zend extension 'xdebug.so' (tried: /usr/lib/php/20180731/xdebug.so (/usr/lib/php/20180731/xdebug.so: cannot open shared object file: No such file or directory), /usr/lib/php/20180731/xdebug.so.so (/usr/lib/php/20180731/xdebug.so.so: cannot open shared object file: No such file or directory)) in Unknown on line 0
04:16:11 Using PHP 7.3.27-9+0~20210227.82+debian10~1.gbpa4a3d6
04:16:14 PHPUnit 8.5.15 by Sebastian Bergmann and contributors.
04:16:14 
04:16:14 Error:         No code coverage driver is available
04:16:14 
04:16:14 ............................S.......SS                            38 / 38 (100%)
04:16:14 
04:16:14 Time: 3.21 seconds, Memory: 365.00 MB
04:16:14 
04:16:14 OK, but incomplete, skipped, or risky tests!
04:16:14 Tests: 38, Assertions: 87, Skipped: 3.
04:16:14 
04:16:14 
04:16:14 You should really speed up these slow tests (>50ms)...
04:16:14  1. 60ms to run MediaWikiIntegrationTestCaseTest:testEditPage
04:16:14 
04:16:14 In CloverXml.php line 69:
04:16:14                                      
04:16:14   String could not be parsed as XML  
04:16:14                                      
04:16:14 
04:16:14 check [--sha1 [SHA1]] [--test-dir TEST-DIR] [--html [HTML]] [--command COMMAND]


Example: https://integration.wikimedia.org/ci/job/mwcore-phpunit-coverage-patch/28411/console
Patch: https://gerrit.wikimedia.org/r/c/mediawiki/core/+/675296

I would like to know why is this happening.


Best regards,
Zoran