Updated Optional Hardening (markdown)

Optional-Hardening.md

@@ -207,9 +207,30 @@ user_pref("privacy.clearOnShutdown_v2.formdata", true); // Saved form info
 For Option 2, you can create exceptions to stay logged in to some sites between sessions.
 * `☰` *→ Settings → Privacy & Security → Cookies and Site Data → Manage Exceptions*
 
+***
+### Service Workers
+Service workers cache a web page's content before it loads, which allows the content to load a few milliseconds faster on return visits. Service workers also let you receive [push notifications](https://support.mozilla.org/en-US/kb/push-notifications-firefox#w_how-do-i-stop-firefox-asking-me-to-allow-notifications) from sites even after you close the site, behavior which Betterfox [blocks](https://github.com/yokoffing/Betterfox/blob/392c62a03c0d63e323a9aae55bc9aff87454db16/Securefox.js#L1461-L1467) by default.
+
+Service workers are scripts any website can install silently. They persist after you close the tab and maintain contact with the remote server. For instance, sites like Reddit use them for caching notifications when the site isn't loaded and telemetry (notification interactions). You can see yours at `about:serviceworkers`.
+
+Service workers phone home to sites you’ve already closed; and when you close a tab, you likely don’t want that site sending you notifications anyway. The minor speed improvement is not worth the loss of control.
+
+This is a pretty mild setting to disabled. I've left service workers disabled for months and never ran into any site issues.
+
+```javascript
+// PREF: disable service workers
+// This will break push notifications (blocked in Betterfox by default).
+user_pref("dom.serviceWorkers.enabled", false);
+user_pref("dom.serviceWorkers.privateBrowsing.enabled", false);
+```
+
 ***
 
 ### JavaScript Optimization
+
+> [!WARNING]
+> You may experience site issues with the options below.
+
 #### How compiler optimization works
 Browsers use a tiered system to process JavaScript: