Add a way to show the Boss Bar to players · Issue #728 · SpongePowered/SpongeAPI · GitHub
How to Use the Data Command in Minecraft
Found out how to change boss bar colors in 1.9 : r/Minecraft
Bossbar and scoreboard that sync to the hotbar slot that is selected. (Snapshot 18w05a) - Commands, Command Blocks and Functions - Redstone Discussion and Mechanisms - Minecraft: Java Edition - Minecraft Forum - Minecraft Forum