docs for extras development?

Can someone point me to where updated docs are on developing extras for the latest modx.

Also, what's the best way to set up a dev environment for developing extras? Thanks!

I think these are pretty up to date
http://rtfm.modx.com/display/revolution20/Developing+an+Extra+in+MODX+Revolution

I think that because there is a similar page for developing an extra for revo 2.1 and earlier:
http://rtfm.modx.com/display/revolution20/Developing+an+Extra+in+MODX+Revolution+-+MODX+2.1+and+Earlier

There is some information here that might be helpful: http://bobsguides.com/mycomponent-tutorial.html.

I'm working on a new, much more automated version, but it won't be available any time soon.


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