Looking to get a used #ereader. Found a nice table of file format support on good old #wikipedia

https://en.wikipedia.org/wiki/Comparison_of_e-readers#File_format_support

Unsurprisingly, amazon is the only company to support their proprietary .azw format and not the otherwise open-standard .epub 🤡

More surprisingly, #eink is a brand name of the E Ink corp. who pretty much have a monopoly on 'electrophoretic display technologies' 😕