code: def browse(ctx):
      
      page_html = Path(ctx.config.sphinx.destdir)/"html"/"index.html"
      if not page_html.exists():
          build(ctx, builder="html")
      assert page_html.exists()
      open_cmd = "open"   # -- WORKS ON: MACOSX
      if sys.platform.startswith("win"):
          open_cmd = "start"
      ctx.run("{open} {page_html}".format(open=open_cmd, page_html=page_html))
docs: Open documentation in web browser.