[SonicTheSith]

Nope, public repos have license, often open source licenses that state that you can freely use the code, or change it , but only if the resulting product will also be opensource.

Other licenses such as the MIT license require that you name the original creator.

[Dylan16807]

You don't need to accept that license to download and read the code.

A license allows new uses that copyright would otherwise block. Some kinds of AI training are fully local and don't make the AI into a derivative work, so they don't need any attribution and you don't need to accept the license to distribute.

[oneeyedpigeon]

But no license (that I'm aware of) says "You are allowed to read this source code, but you may not produce work as a result of learning from it"; for a start, that would clearly be impractical to enforce.