To sum up: the ‘sign’ ‘signals’ what is ‘significant’ enough to merit closer attention.

An excellent summary of what “nimitta” meant in the suttas and their commentaries.

Bhante Analayo was, however, mistaken in saying that:

With full awakening, all misleading notions and ‘signs’ of permanency are forever left behind.

The mistaken notion of permanency is overcome at Stream Entry. With full awakening, the illusion of a ‘self’ who does the perceiving is what is left behind.