.HTB File Extension
File TypeAudacity Help File
What is an HTB file?
Help file used by Audacity, a free sound editing program; stores a compressed archive of Windows help files, .HTML files, and images; used for displaying help information when selecting in Audacity.
HTB files are stored in a .ZIP format. Therefore, you can rename their extension to ".zip" and decompress them with any ZIP decompression utility.