Prefab Variants Editor Window
Unity 2018.3 introduced new prefab workflow which includes prefab variants. Inspector for prefab variant asset shows only base prefab for the variant. Thus understanding of prefab variants inheritance can become a hard task as user have to select base prefab in the inspector to check its base etc. Prefab variants editor window adresses this issue via showing all prefab variants inheritance chains in one go via tree view.
Access project settings select window via Unity toolbar: Window->Pump Editor->Prefab Variants.
Editor window shows prefab variants as ineritance chains starting from most derived variant. So regular prefab will always be the innermost object for every chain. Editor window does not differentiate chains which are parts of bigger chains, meaning that if you have base prefab Animal and variant of it Mammal and you also have variant of Mammal which is called Cat, both Mammal -> Animal and Cat -> Mammal -> Animal chains will be present in the editor window.
Search bar at the top allows to search prefab asset by name. Prefab info panel at the bottom shows selected prefab asset object field and base prefab object field to be able to ping assets in the project view.
As tree view is used for prefabs display, it's possible to navigate in the tree with arrow keyboard buttons. Clicking expand/collapse button while holding Alt keyboard button will expand/collapse all hierarchy of corresponding object.