I woud like to cross-reference an unnumbered section in a quarto book. The quarto docs say this is possible, but I cannot figure out how.
If I want an unnumbered chapter, I'd use this:
# Setup {.unnumbered}
If I want a label I can refer to later with [Chapter -@sec-setup], I'd use this:
# Setup {#sec-setup}
However, combining these in any way I can think of doesn't seem to work. Neither of these work:
# Setup {#sec-setup} {.unnumbered}
# Setup {#sec-setup, .unnumbered}