Appears to be an obscure clay (because I haven't heard of it haha).

https://en.wikipedia.org/wiki/Clinoptilolite#:~:text=Clinoptilolite%20is%20a%20natural%20zeolite,3(Al%2CSi)

Also called a zeolite, it has a strong affinity for Nh4+ (ammonium) which is why it's sold as a deodorizer for barns.

I can't imagine it would hurt anything in the garden as far as toxicity (it is, after all, a natural product and approved by OMRI according to the product info in your link). I'd only be concerned with its potential physical properties.

I don't know if it's been roasted like common cat litter has, or if it's just granulated clay. In the absence of detailed info, it's probably safer to assume it would dissolve and become a clay. So, do you want clay where you would be using it?