Just added editor extensions to my project for the first time (2.54.181105). I have the 2.11.161017 SDK installed.
Your docs say that 2.0+ is supported but I'm getting a compile error from the extensions code.
Assets/PlayFabEditorExtensions/Editor/Scripts/Panels/PlayFabEditorPackages.cs(8,42): error CS0118: `PlayFab.Editor' is a `namespace' but a `type' was expected
This is the error line.
public classPlayFabEditorPackages: Editor
The problem is because Editor here is actually PlayFab.Editor.
And in the SDK there is a file named PlayFabHelp which defines this namespace
namespace PlayFab.Editor
Fully qualifying with UnityEditor.Editor fixes it.