Is it possible to exclude appendix slides of the total number of slides?

Question

In the example below, I have 3 slides: main content, appendix title and appendix content. However, I'd like to exclude the two appendix slides from the total count on the bottom right.

The expected output is to have 1/1 on the bottom right. How can I do that?

---
format: 
  revealjs:
    slide-number: true
---

Slide with main content

# Appendix {.appendix}

---

Slide with appendix content

Answer 1

Resolved here: the solution is to write a Lua filter to automatically apply visibility="uncounted" to all slides in the "Appendix" section.

custom.lua

local in_appendix = false

Header = function(h)
  if h.level == 1 then
    if h.classes:includes("appendix") then
      in_appendix = true
      h.attributes["visibility"] = "uncounted"
    else
      in_appendix = false
    end
  end
  if h.level == 2 and in_appendix then
    h.attributes["visibility"] = "uncounted"
  end
  return h
end

---
format: 
  revealjs:
    slide-number: true
    filters: [custom.lua]
---

Slide with main content

# Appendix {.appendix}

##

Slide with appendix content

##

Another slide with appendix content