I was trying to figure out how to make a chrome extension (new to experimenting with this) that would automatically close a tab if the URL contained a specified string, but everything I've read says you can't do that in javascript - trying to do so with window.close() just generates the error message "VM145:1 Scripts may close only the windows that were opened by it."
However, I've just found out that an extension exists that will do exactly what I wanted to do (tested - works on the latest version of Chrome), called "Tab Close Gold" - how could this be working if Javascript can't close tabs?