Lots of package will likely get outdated after some time it has been uploaded by the maintainer, so editing (forking) a package should be relatively easy by default (unless the maintainer doesn't want it to be). So here is a list of ideas :

Package License: Like in a github repository (screenshot below), each package could specify a type of licence, and this type of licence will have a short display that will tell the user what he can do with the package (Will also list if he can fork the package or not)

Package forking: Forking a package should relatively be easy, especially if a github repository is mentioned. It should be also easy to to search for forks of a package so a user can search more easily some modified versions of a package. I don't have some ideas right now of how it can be implemented, but i will update this discussion if i find some.

Inspiration from other game: Some Publishers and IP Holders will likely don't want a Package/Asset to have their name on it especially if they don't have any relations to it. So one way could be to add another filed into package, that will be different to tags called "Inspired from", it will be a repository of games, movies, animes. So developers will be able to specify from wich game their Asset/Package is inspired from.

So if a user wants to have a Star wars experience, instead of searching only for games that has part of the title star wars, it will search on "Inspired from" the Star wars Saga, and every package/asset based on that will be display even if the name does not include it.