Personas Plus is retiring on November 30th, 2018. After many years of helping users create and access themes, and following the modernization of theming technology for Firefox, it’s time to say goodbye to Personas Plus and to say hello to Firefox Color, Mozilla’s new tool for creating custom themes.
Personas, also known as lightweight themes, is a way of creating Firefox themes, now deprecated. To learn about its replacement, check out the documentation on themes on MDN.