What email header will GMail use to state the distribution list an email came from?

For example:

• customer sends email to support@company.com
• support@company.com is a distribution list which automatically forwards the message further to mary@company.com and joseph@company.com
• My application subscribes to mail coming into mary@company.com and joseph@company.com using the GMail api: https://developers.google.com/gmail/api/reference/rest/v1/users.messages/get

When my application receives the Message from Google, where can I find the distribution list's address (support@company.com)?

I have tried reading emails received via distribution lists from the GMail api and inspecting their headers. But since I cannot find the official documentation on the topic, I do not know if my anecdotal experiment was comprehensive enough.