How to write the first move of a PGN that starts with blacks?

Question

Some programs/websites use 1. ... e5 2.f3 (e.g Arena or LT-PGN-Viewer) while others use 1...e5 2.f3 (e.g chess.com). To achieve this, I loaded a FEN that is black-to-move, then made a move.

Which one is best to use? What does the specs say about this?

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Just to make this clear, my question is not about using 3 dots after a white move comment, for this one I got to the conclusion that it is best to use 1.e4 { comment } 1...e5 2.Nf3 over 1.e4 { comment } e5 2.Nf3, but it is somewhat optional.

Answer 1

1...e5 is best. I quote from Section 8.2.2.2 of the PGN specification, with the relevant phrases in bold:

There are two export format move number indication formats, one for use appearing immediately before a white move element and one for use appearing immediately before a black move element. A white move number indication is formed from the integer giving the fullmove number with a single period character appended. A black move number indication is formed from the integer giving the fullmove number with three period characters appended.

All white move elements have a preceding move number indication. A black move element has a preceding move number indication only in two cases: first, if there is intervening annotation or commentary between the black move and the previous white move; and second, if there is no previous white move in the special case where a game starts from a position where Black is the active player.