Provenance is becoming a procurement question rather than an ethics one. Platforms read it, an increasing number of client legal teams ask for it, and answering "none" is a slower answer than it was two years ago.
It cannot be retrofitted. A manifest describes the steps that were recorded as they happened, so a finished cut with no provenance stays a finished cut with no provenance. If a client needs it, it goes in the brief.
Provenance and a visible label do different jobs. The manifest satisfies machine detection; the on-asset label satisfies a person at first exposure. Article 50 asks for both in effect, and a screenshot strips only one of them.
Can provenance be added to a finished file?
Not meaningfully. A manifest records steps as they happen, so it has to be configured before production rather than attached afterwards.
Is provenance metadata enough on its own?
Not for deepfake-category content. Machine-readable marking addresses detection; a person at first exposure needs something visible on the asset.