There's not a "default" answer to that because it IS in the grey area - Please post a link to the package (asset store url) and I'll flag it so Nellie and the rules team can determine whether or not to approve it :)
Thanks!
Viewing post in Package manager grey area
Gotcha! here it is: https://assetstore.unity.com/packages/tools/animation/leantween-3595
And to note, every unity running 2020+ has it in the package manager