Learning to count?

1

I have noted a couple of instances of this appearing in a comment - usually in an older post:

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(From Mobbed by Mallards | Observation | UK and Ireland | iSpot Nature)
It’s the ‘1234’ that strikes me as odd. Has this replaced something else that’s no longer relevant?

2

Could it be from an old footer that the person deleted and replaced it with just those characters (or the system did).