Okay, then "d" tag is just an identifying string. Then we need to figure out a pattern for that, that other clients might be able to emulate. That's traditionally ISBN, but we won't always have those.
Maybe some sort of hash.
Discussion
You can do whatever as long as it’s unique. I normalize the title and add a random value at the end
“This is a title” turned into “this-is-a-title-6775466”
From then the title tag can change but the d tag must remain the same
I didn't realize that you add that number. All I see in the raw json is "this-is-a-title". 🤷♀️
So I assumed that it's a subject, not an ID.
That's why I've been writing simple things like "john-1", to denote "The First Book of John from the New Testament Bible", so that all of the entries can be found and line up under each other, on Wikifreedia. Since there will eventually be 20+ "john-1" entries for the different Bible editions.