This is Calyx.net, a free VPN service offered by The Calyx Institute as part of its non-profit mission. You can use this VPN on Android phones by downloading the CalyxVPN application from F-droid. You can use it on Linux, Windows and Mac systems by downloading the Bitmask client from this page.
I created an account with them and then I could use the VPN with the Bitmask App (https://www.directory.trade-free.org/goods-services/bitmask/). That was it. Because there are no ads and they don’t sell any premium features I consider the creating-an-account a microtrade. However I give a block less because of this. I also installed the Calyx VPN on my phone and except a small popup once which was asking for donations I couldn’t find any trades. I give 4/5 blocks.