MKVToolnix is described as 'Set of tools to create, alter and inspect Matroska files under Linux, other Unices and Windows. They do for Matroska what the OGMtools do for the OGM format and then some. The latest builds now have the ability to create WebM compliant Files' and is a very popular Video Converter in the video & movies category. There are more than 25 alternatives to MKVToolnix for a variety of platforms, including Windows, Mac, Linux, Web-based and Android apps. The best MKVToolnix alternative is FFmpeg, which is both free and Open Source. Other great apps like MKVToolnix are Shutter Encoder, MakeMKV, MKVExtractGUI and gMKVExtractGUI.
"Warning: Potential Security Risk Ahead. Firefox detected a potential security threat and did not continue to videotofiles.tk. If you visit this site, attackers could try to steal information like your passwords, emails, or credit card details".