Since the entire Elasticsearch codebase is now under SSPL, there's no more distinction between the former Apache-2 code and the x-pack code.
However it seems that they will be moving the free modules which were previously only licensed under Elastic License to be licensed under SSPL instead.
At least, that is what this graph seems to be indicating to me. https://images.contentstack.io/v3/assets/bltefdd0b53724fa2ce...
Unless they plan to make those modules paid which were previously free, which I doubt