I am not sure at what point it has happened, but there is an Egypt Hieroglyphs Unicode block, https://en.wikipedia.org/wiki/Egyptian_Hieroglyphs_(Unicode_block) . While I am not sure if it covers 100% of the characters the extension supports, I think it would make sense to have an option to switch between images and plain text Unicode characters, the same way as there is a preferences section to choose the preferred <math> output.