Ask HN: How can I tell if a chrome plugin is safe?

I would like to use chrome (chromium, actually) with incognito TABs - not windows, so that I can have multiple tabs with no session sharing between them. I just found a plugin that does this - Incognito This [1]

But recently I've seen some news here about how dangerous chrome plugins can be. So I'm not sure if this plugin is safe, especially given the permissions it needs:

- Access your data on all websites (this one worries me a little) - Read and modify your bookmarks - Read and modify your browsing history - Access your tabs and browsing activity

So, in general, is there any way I can tell if a chrome extension is safe? (meaning: it won't be changing page content and/or capturing user input it's not supposed to')

[1] https://chrome.google.com/webstore/detail/incognito-this/icnaplnkjfjncegmphmlfpggildllbho