Typically, if you need to access package private things, you're doing it wrong.
If you absolutly MUST access package private things you should use reflection.
If you ABSOLUTLY MUST access package private things repeatidly and you think that it is something other modders would like to have access to, submit a PR to get it on the official AT list in forge, or write your own coremod.
But, in reality, 99% of the time when a modder thinks they need to do something stupid like that, they are wrong.
Explain what you are doing and someone will probably point you in the right direction.