Mark classes final #196

Job	Run time
Linter	1m 26s
Security checks	21s
Quality control	30s
Unit tests, PHP ${{ matrix.php-versions }}, ${{ matrix.operating-system }}	0s
Code coverage	0s
Unit tests, PHP ${{ matrix.php-versions }}, ${{ matrix.operating-system }}	-1s
Cleanup artifacts	-1s
	2m 15s

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