Paratext won't mark \xt text as linked in Extra Books, so how do I tell Paratext these books contain cross-references?

Question

We use \xt ...\xt* all the time in Paratext and in many places, like Topical Index, Read through the Bible, Glossary, etc.
But when I use \xt ...\xt* in an XXbook Paratext does NOT activate the link nor validate it.
How do we get Paratext to treat XXBooks like all the other books (like GLO, OTH, FRT, TDX, BAK, etc.)?

And why o why did they limit XXbooks to just A - F and we can't change the labels we see? This seems like it wouldn't be difficult to add.
\id XXA - Selaru - Liturgy

We need a "manage" extra book list dialog like we have for Scripture Reference Book Names.
XXA   Lit.    Liturgy     Sunday Liturgy
etc.

Answer 1

I tried the basic checks on XXA, and they actually do check \xt ...\xt* cross references.
But the icon for "View in Quick Reference window" is missing.  You could file a bug report for that.