1. Enable tooltips. (F3+H)
2. Open creative inventory. (E)
3. Look for potions or spawn eggs or potions. They appear as Water Bottle (#0373/0), Spawn Creeper (#0383/0), {{Splash Water Bottle (#0438/0), and Lingering Water Bottle (#0441/0. There are actually no data values.

Why it's a glitch: The old spawn eggs had numbers, as their network ID (for example, the creeper's is 50, so it used to say Spawn Creeper #0383/50). Now, it is NBT tags, not damage values, and ones without data values, (like cobblestone) say just the number (Cobblestone (#0004))