File Extension HPK File Format Compressed archive (HPACK) HPK stands for Compressed archive (HPACK). This was last updated in March 2012 By Margaret Rouse Browse File Extensions Alphabetically: A B C D E F G H I J K L M N O P Q R S T U V W X Y Z # Ask a Question. Find an Answer. Ask your peers a question about this file extension. Ask a Question Data deduplication and compression PowerShell 5 – zip and unzip What is the range an image can be compressed?