Shopify Marketing Consent

[gc101]

For clients I work with, we will be expected to synchronize marketing consent between Shopify and their ERP. As such we need to understand when Shopify records a marketing consent, where it is recorded, and how and when it can change. 

I'm trying to get confirmation on the following questions

1. How can I access it via the API (REST)?
2. Is there a history of updates that can be accessed via the API or backend of Shopify?