Jenny Everywhere is a character that exists in every version of reality. As such, she can appear in any work, as long as it contains the following disclaimer:
"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."
I had seen Jenny briefly, but got more interested after E.H. fan Gwen Patton started her own webcomic featuring Jenny. Gwen's version is the one in the black jacket; others are Don Martin style, a typical Cro-Magnon, "Peanuts" style, and a Pierson's Puppeteer.