> Telegram is not truly open source. Here's Telegram FAQ [0] Q: Why not open sou...

> Telegram is not truly open source.

Here's Telegram FAQ [0]

    Q: Why not open source everything?
    All code will be released eventually. We started with the     
    most useful parts — a well-documented API that allows developers to build new Telegram apps, and open source clients that can be verified by security specialists.

[0] https://telegram.org/faq#q-why-not-open-source-everything