chore: placeholder articles

knowledge base/push notification.md

@@ -0,0 +1,33 @@
+# Push notification
+
+## Table of contents <!-- omit in toc -->
+
+1. [TL;DR](#tldr)
+1. [Further readings](#further-readings)
+1. [Sources](#sources)
+
+## TL;DR
+
+## Further readings
+
+- [`ntfy`][ntfy]
+- [Pushover]
+
+## Sources
+
+All the references in the [further readings] section, plus the following:
+
+<!--
+  References
+  -->
+
+<!-- Upstream -->
+<!-- In-article sections -->
+[further readings]: #further-readings
+
+<!-- Knowledge base -->
+[ntfy]: ntfy.md
+
+<!-- Files -->
+<!-- Others -->
+[pushover]: https://pushover.net/