Some repositories use mkey as a shortened variable name for "Member Key" – a unique token that allows a player to join a modded server without a password.
In more technical circles, "MKey" is frequently associated with USB dongle emulation mkey github
Many security-focused projects use mkey as a variable name for or memory key . Searching GitHub reveals: Some repositories use mkey as a shortened variable
Being MIT or GNU licensed, these tools are free for both personal and commercial use. mkey github