The org.hibernate.bytecode.spi.InstrumentedClassLoader is a little utility we don't use ourselves anymore. It's simple enough that anyone needing such a thing could re-implement it themselves so I suggest we remove it.

Same for org.hibernate.bytecode.spi.ByteCodeHelper: it has no use within our own runtime code, but it's used by tests - so I'd move it to the testing utilities.

Since these are SPIs I’m proposing the change for 6.2, without need for a deprecation cycle.

I’ll send a draft to check if this is agreeable.