There is nothing strange about this capsule…

The Ordinary Capsule behaves like a Crystalarium, except for instead of duplicating gems and minerals, it can be used to produce animal items like eggs, milk, and truffles or monster drops.

Spoiler Warning
The Crafting Recipe for Ordinary Capsules unlocks after a certain event.

Ordinary Capsules is safe to add/remove at any time. If you have any Ordinary Capsules crafted, and you remove this mod, they will all revert to Strange Capsules.

For ease of use, it is recommended to set config options from Generic Mod Config Menu.

BreakChance - The chance that an Ordinary Capsule will break.
DefaultProductionTime - The default time it takes to duplicate a supported item.
DuplicateEverything - Duplicate any item you put into the Ordinary Capsule.
UnlockAutomatically - Unlock the crafting recipe automatically.

See here for the current status on translations.

Check out my other mods

Better Chests - Adds enhanced chest features to the game.
Expanded Storage - Allows Content Pack Creators to add custom storage to the game.
Toolbar Icons - Framework for adding Toolbar Icons that can be used instead of hotkeys or commands.
Helpful Spouses - Has your Spouse perform a random chore every morning.

Feel free to visit me on my Discord server for announcements and early access to beta releases of my mods.

You're also welcome to seek support or submit issues there. You can also find me on the Stardew Valley discord in #making-mods (LeFauxMatt).