I understand that jQuery.browser is now being depreciated, but while it still exists in jquery and is being used for backwards compatibility and plugins it should be maintained.

What I am going to be talking about here is the jQuery.browser.version...

(userAgent.match( /.+(?:rv|it|ra|ie)[\\/: ]([\\d.]+)/ ) || [0,'0'])[1]

As you can see it has 4 checks...

rv=Revision of the Gecko "layout engine".

it=Version of the WebKit "layout engine".

ra=Version of Opera, NOT Presto it's layout engine.

ie=Version of Internet Explorer, but NOT Trident it's layout engine.

Not only that but Opera 10 has two version numbers, one at the start which is 9.80, and one at the end which is 10.00.

As per this article here: http://dev.opera.com/articles/view/opera-ua-string-changes/

There are thought to be no more than 20 notable (text-based or graphical) layout engines in the world.

See: http://en.wikipedia.org/wiki/List_of_layout_engines

So I ask, is this actually meant to be engine.version or is browser.version simply wrong?

I imagine it depends on usage or perhaps both should be supported.