DEV 0.1 is a release file of the Minecraft mod The Mytheral Mod, made for Minecraft 1.7.10. It was published on September 11, 2014 and is 0.2 MB in size. For the full description, screenshots and every other version, visit the The Mytheral Mod mod page.
How to install: Put the .jar into the mods folder (.minecraft/mods) and start Minecraft with the matching mod loader profile.