You do not need WinRAR at all. Two open-source champions have made the rarreg.key completely obsolete:
Adding SSH Key to GitHub:
Many "rarreg.key" repositories are uploaded using stolen or hacked GitHub accounts. By downloading from them, you signal to attackers that your IP address belongs to someone willing to use cracked software—making you a target for future phishing or malware campaigns. rarreg.key github
Before understanding the controversy, you must understand the file itself. You do not need WinRAR at all
WinRAR, developed by Eugene Roshal and distributed by win.rar GmbH, uses a proprietary licensing system. Unlike modern software that relies on cloud validation or online logins, WinRAR uses a simple RSA-encrypted plaintext file named rarreg.key. Adding SSH Key to GitHub :
Distributing or downloading a cracked license key violates copyright laws in most jurisdictions (including the DMCA in the U.S. and EUCD in Europe). While individual end-users are rarely sued, companies and organizations caught using unlicensed WinRAR copies face audits, fines, and legal fees.
An arrange.key file might be a specific type of file used by a particular software or firmware to layout a keyboard's keymap. The exact format and purpose can vary: