Are these really ISO 639-1?

[lazarljubenovic]

The Readme mentions that the list is ISO 693-1. According to ISO, it "provides a 2 letter code that has been designed to represent most of the major languages of the world". However, this repository contains three-letter codes as well. At a quick glance, it seems like these are a combination of 693-1 when available, and then falls back to 693-2 or 693-3. Is this the case? Would love to see this information stated in the readme as well.

[umpirsky]

Yes, I'm also curious what 3 letter codes there are, I guess 693-2 or 693-3.

[eighthave]

What @lazarljubenovic describes sounds right to me. Though perhaps not strictly following a given standard, it is pretty common practice.