API Replace Extension subclasses #609

Job	Run time
ci / Context	1s
ci / Generate matrix	18s
ci / Check governance	0s
ci / 8.3 prf-low mysql57 phpunit all	6m 6s
ci / 8.3 mariadb phpunit all	4m 46s
ci / 8.3 mysql57 phplinting	2m 30s
ci / 8.3 mysql57 endtoend root job1	6m 30s
ci / 8.3 mysql80 endtoend root job1	6m 20s
ci / 8.3 mysql57 endtoend root job2	8m 7s
ci / 8.3 mysql80 endtoend root job2	7m 41s
ci / 8.3 mysql57 js	4m 57s
ci / 8.3 mysql57 doclinting	2m 39s
ci / Dispatch tag patch release	0s
	49m 55s

Provide feedback