The join.me for Google Calendar Chrome extension does not monitor or save your viewing history in any way. These permissions are not new to the extension, however the latest release has caused Chrome to ask you once again for permissions you already granted.

This is happening because the join.me extension requires the "tabs" permission. What's the tabs permission? In non-technical terms, let's just say it's nothing to worry about. But if you are the curious type, the nice folks at Google explain it in a lot more detail here. But otherwise you can feel safe granting these "new but not new" permissions to the join.me extension.

And if you are really curious for more info about Chrome warnings and permissions, visit this Google site: https://developer.chrome.com/extensions/declare_permissions