Is it legal to make modifications to a Package (and publish them)?

Some packages are not available on github, so there is no way to fork them.
Can modified packages still be published?
I’d like to publish some code that uses a slightly modified Entities package.

Thanks

i woudnt think so because alot of assets are availale for comercial profit but i would check to see if the asset has a terms of service or what ever because i think thats up to the owners of the asset you could rewrite the code and use the asset as a dependency to avoid any troubles with completly republishing a existing asset with the original dev\devs

i know some have multiple assets in one but they usaly have at least on dependency such as this never used it never bought it so i cant realy tell anything other than it looks like something that would work for some sort of arma clone or something simaler Squad Shooter Ultimate | Systems | Unity Asset Store

He’s referring to unity-published packages from package manager, not to commercial assets from third parties.

Sorry for the confusion, I was indeed talking about unity-published packages.