Jenny Everywhere is a character specifically and intentionally designed and created to be an open-source character. This is The “License” that was created to go along with Jenny Everywhere since the day she was released:
The character of Jenny Everywhere is available for use by anyone, with only one condition.
This paragraph must be included in any publication involving Jenny Everywhere,
in order that others may use this property as they wish.
All rights reversed.
The “License” should be self-explanatory. However, it should be clarified that it does not mean everything with Jenny Everywhere is free-use and uncopyrighted. People may still maintain copyrights on their own unique character(s), character styling(s), story(ies), artwork, and title(s).
The name, the character herself, and the idea of the character, however, are uncopyrightable, because she already belongs to everyone. That is what is meant by the “All Rights Reversed” portion.
The Shifter Archive interpretation:
This doesn’t need to be placed on every single page one may use her in, as far as a comic in concerned. Typically the first appearance and/or a cast page, or accompanying post, is enough. This isn’t limited to comics either, but for any media that one may use Jenny Everywhere. Audio, comics, assorted art, video, film, modeling, etc.
One likely won’t need to repeat this phrase verbatim if they are cosplaying as Jenny. However, if they are in a contest, they should clarify that it isn’t one’s original character. To the judges, especially to judges, they should give The “License” mantra and maybe this website.
Copyleft: A play on the word “copyright”. It is a form of licensing to maintain copyrights and conditions for use of a material or work, from the original and subsequent uses. Copyleft is very similar to how Creative Commons works, but Copyleft came beforehand, technically originating in software sharing. (Wikipedia Link)
All Rights Reversed: This is a phrase used to indicated a release of a copyleft (or copyright) licensing status. A play on “all rights reserved” since there are none, and works against it. (Wikipedia Link)