Hello Adam,
Thank you for reaching out to us.
Looking on the screenshot provided, I'm afraid that this isn't available in the API. We can raise a feature request for this; however, before raising such, could you provide us your use case as to how the availability of this field would impact your business need.
As an aside, you can actually use this guide to check if a certain UI field is available in the API. You can then use this guide when mapping AdWords API reports to Google Ads API resources.
Regards,
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| Mark Kevin Albios |
| Google Ads API Team |
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