Running php8.3 shows serialize failures, it seems a committed data/messageindexdata.ser is used, maybe that needs to be refreshed to work with all newer php versions?
There were 4 errors:
1) MessageIndexTest::testMessageIndexImplementation with data set #0 (TestableDatabaseMessageIndex Object (...))
unserialize(): Extra data starting at offset 3692475 of 3692476 bytes
/workspace/src/extensions/Translate/tests/phpunit/MessageIndexTest.php:164
/workspace/src/extensions/Translate/tests/phpunit/MessageIndexTest.php:172
=== Logs generated by test case
[objectcache] [debug] MainWANObjectCache using store {class} {"class":"HashBagOStuff"}
===
2) MessageIndexTest::testMessageIndexImplementation with data set #1 (TestableCDBMessageIndex Object (...))
unserialize(): Extra data starting at offset 3692475 of 3692476 bytes
/workspace/src/extensions/Translate/tests/phpunit/MessageIndexTest.php:164
/workspace/src/extensions/Translate/tests/phpunit/MessageIndexTest.php:172
3) MessageIndexTest::testMessageIndexImplementation with data set #2 (TestableSerializedMessageIndex Object (...))
unserialize(): Extra data starting at offset 3692475 of 3692476 bytes
/workspace/src/extensions/Translate/tests/phpunit/MessageIndexTest.php:164
/workspace/src/extensions/Translate/tests/phpunit/MessageIndexTest.php:172
4) MessageIndexTest::testMessageIndexImplementation with data set #3 (TestableHashMessageIndex Object (...))
unserialize(): Extra data starting at offset 3692475 of 3692476 bytes
/workspace/src/extensions/Translate/tests/phpunit/MessageIndexTest.php:164
/workspace/src/extensions/Translate/tests/phpunit/MessageIndexTest.php:172