For reference https://github.com/symfony/symfony/blob/6.2/src/Symfony/Component/Serializer/Mapping/Loader/schema/dic/serializer-mapping/serializer-mapping-1.0.xsd#L84. So the fix is legit and should be merged.
Yeah the merged PR allows the checker to do its job, the fix was probably legit though. A rebase or rerunning the CI would definitely help here.
Status: needs review
We can close here now that #17295 has been merged.
For the record, see #17314.
Definitely fix #8097.
As said in https://github.com/symfony/symfony-docs/issues/8097#issuecomment-704322521, this issue should be closed now that 4.4 (the lower maintained branch in the docs) can use the special test container.
Feature was added in 3.4, so no need for a