If you are genuinely curious about how hacks work, study the Eaglercraft source code on GitHub. The official repository shows how the game handles packets. You can write a "cheat" that simply modifies the MovementUtils.java file for speed. This is a fantastic way to learn JavaScript and game networking—and you won't infect your PC.
While not a "client" in the traditional sense, using EaglerForge allows you to load individual mod scripts, giving you more control over which "hacks" you actually want active. How to Install and Play 18 hacked client eaglercraft free
While many of these clients are advertised as "free," it is important to navigate this community with caution as many files shared on public repositories can contain malicious code. Eaglercraft 1.8 Hacked Clients Most development for these clients happens on or via specialized Discord communities If you are genuinely curious about how hacks