Orthographe rationnelle by Valentin Gatien-Baron

While you browse the internet, this extension automatically respells web pages to a spelling of your choice. This is meant to help understand or evaluate spelling reforms in practice.

The extension ships spelling changes for French, but the functionality works for any language that can express a spelling change as a dictionary mapping old spelling to new spelling.

No text or information about what you browse is sent to anyone or anything.

Source code : https://github.com/v-gb/ortografe