.HELP File Extension
What is a HELP file?
File used by Help Viewer, a help documentation viewer included with Mac OS X; contains a bundle of documents, which may include HTML and CSS files as well as indexing information; commonly used for Mac OS X application help documentation.
Help books may be localized for different languages. For example, a help book may include subdirectories for English (e.g., /English.lproj/ directory) or Spanish (e.g., /Spanish.lproj/ directory) translations.
HELP files are commonly included within Mac OS X application bundles (.APP files).