Merge pull request #609 from chombium/patch-1

Document more source types

Author: anita-flegg

deploy-apps/streaming-logs.html.md.erb

@@ -144,6 +144,20 @@ For example:
 2016-06-14T13:44:38.14-0700 [CELL/0]     OUT Successfully created container
 </pre>
 
+### <a id='health'></a> HEALTH
+
+The Diego Cell emits `HEALTH` logs when running health check actions for an app. These logs are generated by the health check binary that monitors app instances. By default, health check log output is suppressed unless an error occurs.
+
+### <a id='proxy'></a> PROXY
+
+Every app container includes an Envoy sidecar proxy that handles the mTLS handshake with the Gorouter and proxies traffic to the app process. The Envoy sidecar emits `PROXY` logs. By default, Envoy runs with a critical log level, so `PROXY` logs mainly appear when Envoy encounters critical errors, fails to start, or is killed due to the container running out of memory.
+
+For example:
+
+<pre class="terminal">
+2026-01-26T13:49:18.72+0000 [PROXY/0]     OUT Exit status 137 (out of memory)
+</pre>
+
 
 ## <a id='writing'></a> Writing to the log from your app