Sorry for the necropost if that's not allowed, but I've been investigating this and just now found this thread. Given the last post here I decided to search around the mobileread wiki, is this the page:
https://wiki.mobileread.com/wiki/Page_numbers ?
If so my question is that it takes as input presumably a byte-offset from the "start" of the book, where the book is the actual .mobi file? So if I have a location (taken from the My Clippings.txt file) I can convert that into a byte-offset position into the mobi file by doing something like (location - 1) * 150? I guess the tricky part would be then mapping that byte-offset into the unpacked contents of the mobi.
Basically I'm trying to see if it would be possible to take highlight locations from the 'My Clippings.txt' file on the Kindle device and map them to the actual source file in an unpacked book, but it would probably be easier to just brute-force search for the actual highlighted contents than to try to do this location mapping, especially since I've only seen mention of mobi so I'm not sure if this works the same with azw3.