IE11 has a reading mode since Windows 8 I think. The replacement Microsoft Edge browser will also include it.
Firefox for Android actually had its own 'reading list' for a while too. Won't be long until Pocket will be on Firefox for Android by default if this is their direction.
Safari's Reading List, no?
Neither Safari nor IE's reading mode sends or shares any data with a third party entity. If you know differently, please share to the contrary.