As per the title. The specific usecase is "in [initializeonload], if the post processing package isn't installed, install it with UnityEditor.PackageManager.Client.Add("com.unity.post-processing")". I can't find anything relevant under the namespace, nor in the c# source. Either a way to do this, or a better way to add the package, would be appreciated. Worst case, I can examine the project's package manifest manually, edit the json, and force the project to reload, I guess?