Set the feature an app capture shows.

{ featureId }: a product Bible episode id, or null for none. The writer's choice: featureSource becomes writer, and choosing the feature a match named confirms it. An edit's raw master follows it. A recording of a stored tour shows the tour's feature: changing it is refused with 400 validation_failed (change the tour's feature instead). A recording counts toward a feature only when it names that feature. A recording that names none is matched from its own name, the page it was recorded on and the tour it ran against each feature's name, pages and tours: a strong match is tagged by itself (marked featureSource: "matched" until the writer confirms it), and any other likely match is offered as suggestedFeature for the writer to confirm or correct. Free.