'How is the itab struct actually having a list of function pointers?

Researching the interface value in go - I found a great (maybe outdated) article by Russ Cox. According to it:

The itable begins with some metadata about the types involved and then becomes a list of function pointers.

The implementation for this itable should be the one from src/runtime/runtime2.go:

type itab struct {
    inter *interfacetype
    _type *_type
    hash  uint32 // copy of _type.hash. Used for type switches.
    _     [4]byte
    fun   [1]uintptr // variable sized. fun[0]==0 means _type does not implement inter.
}

First confusing thing is - how is an array - variable sized? Second, assuming that we have a function pointer at index 0 for a method that satisfies the interface, where could we store a second/third/... function pointer?

go internals

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'How is the itab struct actually having a list of function pointers?

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