I had cleared all the rounds and when it came to taking a decision, they said "something has come up and now they are not in the position where hiring developers is beneficial for them and they shall contact me when they are ready to hire".
I didn't say anything, but, after some time they posted the exact same job opening online.
I asked them why I was not contacted and they said they're making a list of previous developers and I will definitely be contacted. Guess what, I never got any email.
It's clear as crystal. They'll attract good developer by posting a job opening with a lucrative package. They'll get the task done for free by those developer as a part of interview process, they get the code as they ask us to commit it on github and make them contributor and that's it.