nvim-lspconfig/lua/lspconfig/health.lua

local M = {}
function M.check_health()
  local configs = require "lspconfig/configs"

  for _, top_level_config in pairs(configs) do
    -- Only check configs that have a make_config function.
    if not (top_level_config.make_config == nil) then
      -- the folder needs to exist
      local config = top_level_config.make_config "."

      local status, cmd = pcall(vim.lsp._cmd_parts, config.cmd)
      if not status then
        vim.fn["health#report_error"](string.format("%s: config.cmd error, %s", config.name, cmd))
      else
        if not (vim.fn.executable(cmd) == 1) then
          vim.fn["health#report_error"](string.format("%s: The given command %q is not executable.", config.name, cmd))
        else
          vim.fn["health#report_info"](string.format("%s: configuration checked.", config.name))
        end
      end
    end
  end
end

return M