> I think the initialism JDF may already be taken

Acronyms are lossy compression. I’d bet there’s a JDF that even predates the one you reference in one of your descendant comments.

I’d be interested in knowing (though admittedly not enough to look) if there’s even a three letter acronym using the English alphabet that’s not already in use.

That's "JDL", which isn't the same 3 letters.

Whoops, I meant https://www.jewishdefensefund.org/