diff --git a/editions/tw5.com/tiddlers/mechanisms/InfoMechanism.tid b/editions/tw5.com/tiddlers/mechanisms/InfoMechanism.tid
index c56bd47eb..040dd7bd2 100644
--- a/editions/tw5.com/tiddlers/mechanisms/InfoMechanism.tid
+++ b/editions/tw5.com/tiddlers/mechanisms/InfoMechanism.tid
@@ -15,6 +15,7 @@ System tiddlers in the namespace `$:/info/` are used to expose information about
 |!Title |!Description |
 |[[$:/info/startup-timestamp]] |<<.from-version "5.1.23">> Startup timestamp in TiddlyWiki date format |
 |[[$:/info/browser]] |Running in the browser? ("yes" or "no") |
+|[[$:/info/mobile]] |<<.from-version "5.2.3">> Is running on a mobile device? ("yes" or "no" - eg, ''<<example full>>'') |
 |[[$:/info/browser/language]] |<<.from-version "5.1.20">> Language as reported by browser (note that some browsers report two character codes such as `en` while others report full codes such as `en-GB`) |
 |[[$:/info/browser/screen/width]] |Screen width in pixels |
 |[[$:/info/browser/screen/height]] |Screen height in pixels |