How are custom presets created?

[dirn]

I was looking through the config recipes in the wiki and I noticed that it said

-- you can also add custom presets that you can enable/disable with enabled=true```

This seems like a great way to remember why my config is the way it is without having to have comments that run through various levels of the table. Something like

presets = {
  disable_virtual_text = true,
},

is easier to follow than

messages = {
  view_search = false,
},
routes = {
  {
    filter = {
      event = "msg_show",
      kind = "search_count",
    },
    opts = { skip = true },
  },
},

especially when there's more to the config.

I looked through the wiki and :h noice and I couldn't find any instructions for how to register custom ones. Is there a proper way to do this?