This tool, originally a part of the broader Kitserver suite of tools, allows you to repack .pac archive files, which store most of the game data for Hyperdimension Neptunia Re;Birth 1-3, and Megadimension Neptunia VII. Despite what the screenshot may indicate, it will work on all four of the main Neptunia games.

Should Kitserver and Neptools ever lose their ability to load new game content, repacking changed data into the appropriate .pac files will allow you to continue using mods for Neptunia games. You may also wish to repack these files to cut out Kitserver and Neptools from the game completely, should either or both of them cause you any headaches.