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.
Comments
Here's Telegram FAQ [0]
[0] https://telegram.org/faq#q-why-not-open-source-everythingDidn't see that part of the faq... it would be great if they had an ETA.