How Do I Get the API Name of a Custom Salesforce Sync Object
Hello,
I'm syncing an object over from salesforce (AccountContactRelation) into Marketo. I was able to get the object to sync from the contact record and the records seem to have flowed through. 
I was reading that the smart list options were limited for custom objects in the sense that you cannot pull a smart list on it itself, you can only add the 'Has Custom Object' filter and add constraints, which is fine. We can make do with that for segmentation.
However, my understanding from How to Obtain Marketo Custom Object Data is that I can use the marketo API to pull this information.
I'm using a call like
{{base_url}}/rest/v1/customobjects/AccountContactRelationships.json?filterType=ContactId&filterValues=003Rj000005Dsz2IAC&fields=Id,ContactId,AccountIdto attempt tot retrieve the information, but it's returning an error that AccountContactRelationships cannot be found. Normally this means I have the wrong API name. I've tried a few different iterations, but cannot find the actual API name.
So that leads me to two questions:
1. Are Custom Salesforce Objects Synced considered custom objects?
2. If so, how do I get its API name?