Scentia Kindle format is a version of MOBI format.
"A file with the .MOBI file extension is used for storing eBooks. It was originally a Mobipocket Reader format but has since been adopted by several different readers as well. Amazon purchased Mobipocket in 2005, and later discontinued the MOBI format in 2011.
A MOBI file is specifically designed for mobile—or eReader—devices. The format is very lightweight in size and supports bookmarks, notes, corrections, and JavaScript. Also contained in the file, along with the eBook, could be DRM, or copyright protection, to prevent copying and illegal viewing.
The current Kindle formats (AZW3, KF8, and KFX) are based on MOBI and is a proprietary format exclusively used on Kindle devices. And, in fact, you can still open files with the MOBI format directly on your Kindle—you just have to send them to your Kindle first"
I can borrow library books in Kindle format through the Public Library's "Overdrive" app. More about that at
www.wikihow.com/Access-UK-Library-Books-on-a-Kindle or ask at your own library.