Global options (globalOptions or go)

import type { Denops } from "https://deno.land/x/denops_std@v0.2.0/mod.ts";
import { globalOptions } from "https://deno.land/x/denops_std@v0.2.0/variable/mod.ts";

export async function main(denops: Denops): Promise<void> {
  // Set option
  await globalOptions.set(denops, "filetype", "world");

  // Get option
  console.log(await globalOptions.get(denops, "filetype"));

  // Reset option
  await globalOptions.remove(denops, "filetype");
}

Note that globalOption.get() returns defaultValue when the option is falsy.