Why the y-str.org?
There are no specific reasons. Y-Str markers was the first thing I learnt in Genetic Genealogy. While Y-STR markers is specifically for paternal line, the name used here is just to say the website is related to Genetic Genealogy.

How can I trust the downloads?
To enable trust and prove my identity, I had digitally signed all binary downloads from this website using a trusted certification authority (Thanks to CERTUM). Further, all downloads are hosted in Google Drive which has built-in virus scanner for file sizes less than 30 Mb. I still recommend you to scan all files downloaded with an antivirus.

Is the software Open Source?
Yes. All software on this website (y-str.org) are open source. The source code is usually hosted in github.com/fiidau or included within the application inside a src folder.

What is the license for all the downloads?
I am not a licensing expert but a simple part-time open source developer. Where-ever possible, I do abide by the conditions and licenses of the data I take for my work. If there is no mention of license, you can consider it as The MIT License (MIT). All the contents of this website is licensed under a Creative Commons Attribution 3.0 License. So, basically you are free to do whatever you like whether it is software or content, but just mention the source where you took it.