In the web inspector console on any open gmail page:
> gmonkey.info("2.0")
"The "gmonkey" module is not officially supported and is subject
to change, we will support previous versions for at least 1-month.
Use gmonkey.load(v, callback) to load in the full API where v is
the version number of the API you want passed to calback. Latest
set of the bindings is "2.0". kthxbye"
GmailGreasemonkey is definitely useful to any Gmail extension developer. Unfortunately there really isn't much discussion happening around updates and you end up running into little problems such as ready().
I just poked around: there seems to be a 2.0 API.
In the web inspector console on any open gmail page: