I don't know if it is done intentionally or not or if it has any value to Google, but it makes it a lot harder to write browser extensions that interact with th

I don't know if it is done intentionally or not or if it has any value to Google, but it makes it a lot harder to write browser extensions that interact with those sites. (If you open the console when running Rapportive on gmail, for example, you can see through their logging what work is required to overcome it.)