I can attach a file to a Lightning emailTemplate using one of the emailTemplate editors in Salesforce but I have not been able to find the attachment record that makes this relationship possible.
If, for example, I have an emailTemplate with id '00X0t000000MJ24EAG' and I attach a file to it, I can verify that the file is related to the emailTemplate by opening the emailtemplate in the emailtemplate editor associated with the email component on a lead record page. The file will be shown attached to the emailTemplate below the email HTML body rich text editor (image attached). However, when I query the DocumentAttachmentMap object with either of the following two queries, no results are returned (I also queried ContentDocumentLink):
select id from DocumentAttachmentMap where parentID = '00X0t000000MJ24EAG'
select id from DocumentAttachmentMap
How do I find the record which associates the file I attached with the Lightning emailTemplate?