The Adventure docs are currently a work in progress. Some areas may have limited coverage or may not be entirely up to date. Feel free to join our discord at https://discord.gg/MMfhJ8F if you have any questions.
On supported platforms (Sponge 7 and Bukkit), Adventure is able to enhance its functionality by using the ViaVersion API to send packets directly to the client. This allows, for instance, for a plugin on a Minecraft 1.7 server to send RGB chat messages and titles to clients on newer versions of Minecraft.
If you include the Sponge or Bukkit platforms, no further action is required: ViaVersion will be detected and support for it will be enabled.