Updated Optional Hardening (markdown)

Optional-Hardening.md

@@ -39,12 +39,6 @@ user_pref("urlclassifier.features.socialtracking.skipURLs", "");
 
 ***
 
-### DNS-over-HTTPS (DoH)
-See [here](https://github.com/yokoffing/Betterfox/blob/dbaff70e63c74a856c30efbdbace5c63cf655888/Securefox.js#L612-L621)
-```
-
-```
-
 ### Hide cross-site referrer
 :warning: This will break Instagram embeds, Bing login, `MangaPill.com`, some third-party streaming sites, and at times images.
 ```
@@ -56,6 +50,28 @@ user_pref("network.http.referer.XOriginPolicy", 1);
 
 ***
 
+### Disable `default-browser-agent` (Windows only)
+On Windows, Mozilla [collects information](https://techdows.com/2020/04/what-is-firefox-default-browser-agent-and-how-to-disable-it.html) on what you've set as your default browser. However, disabling `default-browser-agent.enabled` also breaks the `Make Default...` button to set Firefox as the default browser.
+
+Add it to your overrides if you do not use this part of the UI.
+
+```
+// PREF: disable telemetry of what default browser you use [WINDOWS]
+// [NOTE] Breaks "Make Default..." button in Settings.
+user_pref("default-browser-agent.enabled", false);
+```
+
+***
+
+### DNS-over-HTTPS (DoH) 
+Setup your DoH settings. See [here](https://github.com/yokoffing/Betterfox/blob/dbaff70e63c74a856c30efbdbace5c63cf655888/Securefox.js#L612-L621)
+```
+user_pref("network.trr.uri", "YOUR_DOH_HERE");
+user_pref("network.trr.mode", 3); // enforce TRR (without System fallback)
+```
+
+***
+
 ## Fingerprinting
 Fingerprinting is a high [threat model](https://thenewoil.org/en/guides/prologue/threatmodel/) issue that is only [addressed](https://github.com/arkenfox/user.js/wiki/3.3-Overrides-%5BTo-RFP-or-Not%5D#-fingerprinting) reasonably by Tor.<sup>[1](https://youtu.be/5NrbdO4yWek?t=4334)</sup>