0805: re-add visited links

It can still be used to mitigate social engineering attacks (e.g. using visibility and user clicks), and advanced/targeted scripts

user.js

@@ -456,6 +456,17 @@ user_pref("keyword.enabled", false);
 user_pref("browser.fixup.alternate.enabled", false);
 /* 0803: display all parts of the url in the location bar ***/
 user_pref("browser.urlbar.trimURLs", false);
+/* 0805: disable coloring of visited links - CSS history leak
+ * [SETUP-HARDEN] Bulk rapid history sniffing was mitigated in 2010 [1][2]. Slower and more expensive
+ * redraw timing attacks were largely mitigated in FF77+ [3]. Using RFP (4501) further hampers timing
+ * attacks. Don't forget clearing history on close (2803). However, social engineering [2#limits][4][5]
+ * and advanced targeted timing attacks could still produce usable results
+ * [1] https://developer.mozilla.org/docs/Web/CSS/Privacy_and_the_:visited_selector
+ * [2] https://dbaron.org/mozilla/visited-privacy
+ * [3] https://bugzilla.mozilla.org/1632765
+ * [4] https://earthlng.github.io/testpages/visited_links.html (see github wiki APPENDIX A on how to use)
+ * [5] https://lcamtuf.blogspot.com/2016/08/css-mix-blend-mode-is-bad-for-keeping.html ***/
+   // user_pref("layout.css.visited_links_enabled", false);
 /* 0807: disable live search suggestions
 /* [NOTE] Both must be true for the location bar to work
  * [SETUP-CHROME] Change these if you trust and use a privacy respecting search engine