How to fetch EmailTemplate details using Admin API?

[dmytrop]

I am building a localization app and use Admin GraphQL API. 
It must be capable of translating email templates and as I can see official Translate&Adapt app can do it. 
There is no problem to fetch and update translatable content.
Where I'm failing is to get/show title e.g. "Order confirmation" by entity ID for example  gid://shopify/EmailTemplate/28492726589.

I have tried to use node query with no luck as it responds that EmailTemplate is not implemented. And there is no EmailTemplate in the list of objects implementing node  

It must be possible somehow because I see Translate&Adapt does it. 

Can you please suggest API to use for this task.
I'm ready to use undocumented/unstable versions.