DarkMagicForNvimApi.lua

if vim.api.orig == nil then
  vim.api.orig = {}
  
  for name, func in pairs(vim.api) do
    vim.api.orig[name] = func
  end

  local default_win_config = {
    border = "single",
  }

  function vim.api.nvim_open_win(buffer, enter, config)
    config = vim.tbl_extend("keep", config, default_win_config)
    return vim.api.orig.nvim_open_win(buffer, enter, config)
  end
end