How are R11 tax groups implemented in R12?

We only have Canadian taxes setup in our system.  We are upgrading from R11 to R12.  We have a tax CLASSIFICATION on every CAD customer shipto and the correct tax rates and tax group name defaults on to the invoice and everything works.

In looking at the upgraded R12 setup, I do not see how the tax group is defined, but it is being used.

I understand that tax groups are obsolete in R12, but they are still showing in the tax classification field and working.

Where can I see this setup??

thanks

Randee