Sounds similar to Apple's "Core Technology Fee", literally a mechanism for sabotaging third party app distribution in the EU.

This is a very big oversight in that EU law.

Allowing third-party "app stores" is completely useless when all apps must be approved by the operating system company.

It's also being abused by google (technically, will be, very soon), I guess they saw that since the legal framework for this kind of thing has now been written, they can do it too.

Except at least there are alternatives to Unity without replacing your entire OS and hardware.