Is it possible to use/create a different dynamic tag ?

Right now the hooks don’t exist to extend the dynamic tags. I’ve added this as an issue to be fixed for the next release, see https://github.com/mtekk/Breadcrumb-NavXT/issues/32

After the hooks have been added it will be up to you to hook into them and provide a handler for %alt_link_text%, or any other tag you want to add/use. Though I’ll provide a tutorial demonstrating the feature.

magic ??

I look forward to that.