Being a jquery plugin not necessarily means it works for every browser jquery supports.
Besides, the only feature used from jquery core itself is $.extend(). The namespace is the only relevant benefit.
Since the plugin depends a lot on the browser environment to work properly I don't see any benefit on documenting just the jQuery versions.

Considering a lot of issues opened because of the complexity of native cookies handling, what about a section for Frequently Asked Questions?
It could be useful as a reference for the most common problems to researchers and serve as a reminder to ourselves, it could suffice:

* Path rules for all cookie operations
* IE semicolon bug
* "file://" protocol security issues on chrome
* Maybe the "Github is not a CDN" thing too?

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Regarding the last question. Watching jQuery development it seems they still use testswarm.