Hotbars+ has been discontinued and archived in favor of Librarian, its successor. It will still work, but you should seriously consider migrating since Librarian has more features and is a drop-in replacement for Hotbars+.
Hotbars+ is a mod for Minecraft that dramatically increases how many hotbars can be saved by modifying the vanilla hotbar storage system to support pages.
The mod works by hijacking the saved hotbar system Minecraft uses to use a different file to load and save from in place of the traditional hotbar.nbt, hot-swapping files for each page.
The requirements depend on the version of Minecraft you're using. To help guide you, here's a table (last updated as of v2.0-pre11):
* = The mod will still launch without it, but you won't be able to run client-side commands like /hotbars+.
