I'm very surprised here. Other software I've used has tons of other files including DLLs, driver files, etc.
Best answer by JimM
Welcome to the Community! That's a great question, and it's actually one that has come up before, so we created a knowledgebase article for it, which you can find here. It's true that the Webroot installation overall is pretty tiny compared to other antivirus software. To answer your specific question, the driver for the program is actually kept in the WindowsSystem32Drivers directory, and the DLL is either in WindowsSystem32 or WindowsSysWow64, depending on whether you're running a 32 or 64 bit version of Windows. The rest of the file locations are detailed in the linked article as well. Did you know Webroot takes up 141X less space than Symantec? :D