It was alluded to in The God-Machine Chronicle rules update:
Description: The subject of this Condition is within the sphere of influence of an angel.
... In addition, characters with the Destiny Merit are always subject to this Condition.
And in Chronicles of Darkness (2e corebook) the Fate Sense Numen also mentioned it:
If using the Fate optional rule, the entity may taste the Fate of a mortal being. The Numen costs 1 Essence, and is contested by Resolve + Supernatural Tolerance. Characters with the Destiny Merit may not contest this Numen. If the entity succeeds, it knows the subject’s Fate and can discern the presence of the Destiny Merit and its rating.
Is there any information from OPP on what the Destiny Merit is/was, if it was removed from earlier drafts in the editing process? Were there earlier drafts posted?