Chrome needs to work on its permissions messages or its permissions model. I developed a stupid simple extension[1] that just kills all the images on a given page, and the permissions required for it to do its work (mostly the `background.html` page communicating with a separate JS file) result in the exact same terrifying message when installing.

Specifically, I think it's the "tabs" permission in my case that causes that message, which I think I needed to ask for in order to have the permission show up as a page action, or something. The memory is hazy now.

(Note: There's a very good chance my extension could be rewritten to not need those permissions, but it was not immediately obvious how to do that when I wrote it, and I haven't poked at it since then.)

[1] https://chrome.google.com/extensions/detail/jjjmnickdhkfpaoc... and http://github.com/mccutchen/ImageKill