Hello! I am extremely interested in submitting a PR for custom item data. The main goals of this patch would be, in order of importance: 1. Ensure that any custom data attached to an ItemStack is maintained 2. Serialize and deserialize custom Item data when using the Bukkit serialization API 3. Provide API access to read and write all Item NBT data The goal here is to allow storage of arbitrary custom data- this is not really meant to be a way to edit the "raw" builtin (vanilla) NBT data, as there are already ways to do that via the API. I had previously submitted a PR to CraftBukkit and Bukkit for this- the was API built on the Metadata API. I'm not sure if this is the best fit for Spigot, and I am interested to hear what people would like. If you are interested in being able to reliably store data on an ItemStack, please leave a message here with any ideas or suggestions you have. I will take this into account as I put a PR together. Thank you!