What is the directory (folder) named “_private” and others beginning with an underscore?

These are needed for FrontPage extensions. Renaming or deleting any of the files starting with an underscore can result in FrontPage working improperly or not at all.

These are needed for FrontPage extensions. Renaming or deleting any of the files starting with an underscore can result in FrontPage working improperly or not at all.