Look how it looks nice:

if data.raw["item-subgroup"]["bob-logistic-tier-1"] then -- bob
  local subgroups = {}
  for item_name, item in pairs (data.raw.item) do
    local subgroup_name = item.subgroup
    if subgroup_name then
      if not subgroups[subgroup_name] then subgroups[subgroup_name] = {} end
      table.insert (subgroups[subgroup_name], item_name)
    end
  end
  log ('subgroups: ' .. serpent.block (subgroups))
end

Can you please also (if bob's mod available) sort items the same way?
Last subgroup tier by bob is:

  ["bob-logistic-tier-5"] = {
    "ultimate-transport-belt",
    "ultimate-underground-belt",
    "ultimate-splitter",
    "express-inserter",
    "express-filter-inserter",
    "express-stack-inserter",
    "express-stack-filter-inserter",
    "ultimate-miniloader",
    "ultimate-filter-miniloader"
  },

hey dark, i would like to have this , too.

could you share your config? im really a fan of this look ;)

Please write the topic on the forum, I make it when I have enough motivation :)
https://forums.factorio.com/viewforum.php?f=33
Maybe someone else made it, but I don't know about it.

To be honest I'm not great with coding and don't actually know how that code works. I've never done anything with Lua tables. If someone wants to submit a pull request I'll look at implementing it. My primary concern is that if in a future factorio update there are bugs, I won't be able to easily fix them. However I do like the look to so I am willing to add it to the mod, I just don't have the time to make those changes myself at the moment. Hopefully it's something I'll have time to look at more in the future.