These are distributed as a single Eaglercraft.html file. You don't install them – you just open the file.
As of 2025, Eaglercraft supports versions 1.5.2, 1.8.8 (the most stable and popular), and 1.12.2 (still in active development). No versions beyond 1.12.2 are currently available. Efforts to backport further features are ongoing, with EaglercraftX receiving continuous updates. eaglercraft 18 mods work
For those looking to create mods, the setup involves a "workspace" that handles the conversion from Java to browser-executable code. These are distributed as a single Eaglercraft