If an existing generated type is removed and then the same type is readded, the type will no longer have any prototypes.

See example outputs when adding, removing, and re-adding the same material from content library view:

First add of material to the project, output from MaterialBrowserView::nodeReparented() listing allExportedTypeNames() for all selfAndPrototypes() of the reparented node of the added type:

node= "Generated.Bundles.Materials.StoneMaterial"
prototype= "StoneMaterial"
prototype= "StoneMaterial"
prototype= "PrincipledMaterial"
prototype= "PrincipledMaterial"
prototype= "PrincipledMaterial"
prototype= "PrincipledMaterial"
prototype= "PrincipledMaterial"
prototype= "QQuick3DPrincipledMaterial"
prototype= "Material"
prototype= "QQuick3DMaterial"
prototype= "Object3D"
prototype= "QQuick3DObject"
prototype= "QtObject"
prototype= "QObject"

After removal and re-adding of the same material, the list of prototypes is much shorter, containing only the self types:

node= "Generated.Bundles.Materials.StoneMaterial"
prototype= "StoneMaterial"
prototype= "StoneMaterial"

This breaks all isBasedOn checks for the node.