An MBP file is known as Mobipocket Notes File but it doesn’t contain the e-book itself; it contains the e-book notes which are created by users in an e-book such as corrections, annotations, drawings, as well as some other important marks. The MBP files just refer to the notes that the users added while reading a certain e-book. On the other words we can say an E-books allow users to add some notes where they want while reading and those notes that are marked are usually saved using the .mbp extension.
Brief explaination about Mobipocket Notes file
The above paragraph shows that Mobipocket Notes facilitate the users to add some notes where necessary and these notes saved in an MBP file. Since these files are entirely associated with an e-book file as they are contained within an e-book, they are usually saved with the e-book too and are located in the similar location where the e-book file is saved. These files are usually produced by the MBP Reader or Mobipocket Reader Desktop program, which is an application useful for reading books electronically. The MBP files are saved in binary format and can be opened using an MBP reader utility.