missing invisible-xml library in BaseX 11.0?

Some days ago I downloaded BaseX110.zip and installed it. When I try to invoke the invisible-xml function documented at [1], however, I get the error message: [basex:function] Function invisible-xml requires missing class: de.bottlecaps.markup.Blitz. At first, I thought this might be interference from an earlier version of BaseX (9.0.1, which is what my package manager offered me), but it persists now even after I have uninstalled that earlier version. Did I do something wrong in the installation? Or was there an oversight putting the zip file together? best, Michael Sperberg-McQueen [1] https://docs.basex.org/main/Invisible_XML