Obfuscate filenames better, double rate limits

Using-the-API/Push-notifications.md

@@ -1,4 +1,4 @@
 Push notifications
 ==================
 
-**Note: This push notification design turned out to not be fully operational on the side of Firebase. A different approach is in consideration**
+See <https://github.com/Gargron/tusky-api> for an example of how to create push notifications for a mobile app. It involves using the Mastodon streaming API on behalf of the app's users, as a sort of proxy.