I’m spending a lot of time debating people about Bitcoin online these days. One issue that I encounter regularly is that my opposite colloquists are unaware of the contributions the Blockstream developers have added to the Bitcoin Core project since the company was founded.

My aim is twofold: I’d like to be able to simply link this question next time I read "Blockstream produces only vapour, and contributes nothing", and I think that the answer to this question deserves more visibility.

Please list what measurable contributions Blockstream developers have made to the Bitcoin project?