Add PotionSlot

src/main/java/org/spongepowered/api/data/Keys.java

@@ -787,6 +787,11 @@ public final class Keys {
      */
     public static final Key<Value<Component>> CUSTOM_NAME = Keys.key(ResourceKey.sponge("custom_name"), Component.class);
 
+    /**
+     * The custom potion effects that are stored on an {@link ItemStack}.
+     */
+    public static final Key<ListValue<PotionEffect>> CUSTOM_POTION_EFFECTS = Keys.listKey(ResourceKey.sponge("custom_potion_effects"), PotionEffect.class);
+
     /**
      * The damage absorbed by an armor {@link ItemStack}.
      * Readonly

src/main/java/org/spongepowered/api/item/inventory/slot/PotionSlot.java

@@ -0,0 +1,32 @@
+/*
+ * This file is part of SpongeAPI, licensed under the MIT License (MIT).
+ *
+ * Copyright (c) SpongePowered <https://www.spongepowered.org>
+ * Copyright (c) contributors
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+package org.spongepowered.api.item.inventory.slot;
+
+/**
+ * An inventory slot which can only contain potions.
+ * e.g. BrewingStand
+ */
+public interface PotionSlot extends FilteringSlot {
+}