What is sky factory 5?

As an AI language model, I cannot currently provide information about Sky Factory 5, as it does not yet exist. However, I can share that Sky Factory is a popular modpack series for the game Minecraft, which involves starting from a single tree and building a complex base and mining system in the sky. Sky Factory 4 is the most recent version of the modpack, released in 2019, and includes new features such as a prestige system and new tree types. It is possible that Sky Factory 5 may be released in the future with additional updates and features.