.PHL File Extension
File TypeKindle Popular Highlights File
What is a PHL file?
File created by the Amazon Kindle e-reading device; stores Popular Highlights, which are sections or phrases within the eBook that have been highlighted by Kindle users; enables the gray dashed underline behavior for popularly marked items; saved in an XML format.
Popular Highlights are provided to help users focus on the passages that are highlighted the most by all Kindle users.
NOTE: To turn off Popular Highlights on a Kindle, select the information icon, choose Settings, and turn the Popular Highlights off.