Pergunta: Explique o conceito de: Interfaces e Classes predefinidas

Interfaces e Classes predefinidas
Índice
Traversable
Iterator
IteratorAggregate
InternalIterator
Throwable
Countable
ArrayAccess
Serializable
Closure
stdClass
Generator
Fiber
WeakReference
WeakMap
Stringable
UnitEnum
BackedEnum
SensitiveParameterValue
__PHP_Incomplete_Class
Veja também as
Interfaces SPL
e
classes reservadas
....