You can add tooltips to any item (including other items from other mods) via a config file located at: config/extra_tooltips/tooltip.json
Default file is structured:

Adding a tooltip looks like:

You can reload config files (When you make a change) by doing /reloadtooltips - Only in singleplayer though. If you would like to reload in multiplayer, you need to join singleplayer world and run the command, then go back to multiplayer, or relaunch your game.
The mod is only required on CLIENT.
Mod can be used in any modpacks.
No files available for download.