I often sideload my ebooks by calibre or use "send to my kindle" to get them in the air. I also make highlights and take notes on my Kindle. Those highlighs and notes are stored in Clipping.txt but to some of my sideloaded books, its also synced online to https://kindle.amazon.com/your_highlights
How can i make my highlights synced to kindle.amazon.com? :help:
How can i make my highlights synced to kindle.amazon.com? :help: