Create new Widget… where is the code for the built in RSS ?

hi there

the title pretty much says it all I want to create a simple widget and would like to base my work on the RSS widget (really i want to change some layout and add some settings where to get the feed from…) I had a brief look and cant see where its implemented and the doc’s appear to be for the old widgets and not 2.5 can you point me to where the RSS widget is in the 2.5 code that I can modify a little ?

thanks for any replies

regards

John Jones