You are right. Closed-source software is not good. I am posting the source code for you to make sure there is no malware included.

Now you can verify the code. If you don't have Labview you can get trial version for free.

Why Labview? It is easy and graphical. Non-text programming. The hardest part in working on WRW was to read python code of Electrum and understand what to do. I am sorry to use propietary IDE but there is currently no open-source graphical IDE for easy non-text programming.

By the way, btcrecover does not support Electrum 3.x wallets. WRW does.