SaintsEditor is a UnityEditor.Editor level component, which gives:

1. All attributes that requires SaintsEditor to be enabled
2. Auto kick-in sub-editor. A serializable class/struct now automatically use SaintsRow (SaintsEditor) to allow many attributes works
3. Auto kick-in drawer. Unity by default loading attribute from top to buttom, left to right. If you write [Range(0, 100), OnValueChanged] by default won't work because Range (Unity attribute) won't fallback. SaintsEdtior will handle the order to make OnValueChanged (SaintsField attributes) to work with Range (other attributes)

Namespace: SaintsField.Playa

Please note, any Editor level component can not work together with each other (it will not cause trouble, but only one will actually work). Which means, OdinInspector, NaughtyAttributes, EditorAttributes, SaintsEditor can not work together.