I’m working on an email reply automation tool using the Intercom REST API. I’m trying to retrieve the email history — the quoted text that appears collapsed behind the three dots (“…”) when a customer replies to an outbound email we’ve sent them.

From inspecting the network traffic, I can see that this data is retrieved via a private Ember API endpoint:
curl 'https://app.intercom.com/ember/inbox/email_history?metadata_id=XXXXXXXXX&app_id=yyyyyyy
Is there an equivalent method in the public REST API to access this email history or quoted content?
I’ve already tried GET /conversations/{conversation_id}, but the response only includes the conversation parts - it doesn’t contain the quoted email thread (the hidden “three dots” section) in either the parts or metadata.
To clarify, customers are replying directly to our outbound emails (sent via our own system, not through Intercom). When we fetch the resulting conversations through the API, we can see the customer’s reply but not the previous email content they were responding to.
I understand that if we sent the outbound messages directly from Intercom, these might appear as separate conversation parts, but that’s not the case in our current setup.
Thanks in advance,
William.