arxiv_filename_change.user.js

// ==UserScript==
// @name         Change filename for arxiv downloads
// @namespace    https://arxiv.org/
// @version      1.0
// @description  Changes filename for the PDF link, so that once you open it in pdf js it downloads as "paper_name.pdf" instead of "year_month.identifier.pdf"
// @author       Nishant Nikhil
// @match        https://*.arxiv.org/abs/*
// @grant        none
// ==/UserScript==

list_a = document.getElementsByTagName("a")
var link_pdf_a;
for (i = 0 ; i<list_a.length; i++) {
  if (list_a[i].href.includes("pdf")) {
      console.log(list_a[i].href);
      link_pdf_a = list_a[i];
  }
}

list_h = document.getElementsByTagName("h1")
title_h = list_h[list_h.length - 1].innerText.replace(/ /g,"_");


link_pdf_a.href = link_pdf_a.href + "&filename=" + title_h + '.pdf'