As far as I know there is no command nor a file to look that up. The last official version seems to be v0.88 (there is an unofficial v0.89 out there) which is pretty old itself I'm afraid.
In case you have not tinkered too much with the original files, you can always compare (diff) them with the ones from the last downloadable version at
https://frug.github.io/AJAX-Chat/ The first files I would probably look into would be:
/js/chat.js
/lib/class/AJAXChat.php
and
/lib/template/loggedIn.html