The main problem is that we only have the binary version of the library, so there's no way to fix bugs on it. We know it's based on an open source library that has already fixed some bugs but as we don't know what was changed in our version we cannot use any new version of it.
So are you commenting the work arrounds you have put in place to get the library working? That is a valid use of code comments, but in your article I don't remember that you mention that. I would be very careful using such a library since it has known bugs and could easily become a security problem.
But still does not answer the question of why do you need to take the orginal source code and put into a public repo in GitHub and then put a link in a code comment in the code you modify. Why do you think that is needed? With good source control tools you can look back at version of the code that was modified that you want to look at. I have never needed to do this nor have I have seen others do it. In fact if I did this at work with out approval I could lose my job.
I haven't said to upload it to GitHub, but put it somewhere. It can be a zip file in GDrive or on a private repo in Bitbucket. You are right that publishing something to Github without permission can be dangerous.
The problem we have is that there's a modified library in the project and we don't know how to update it or change it.
We're a place where coders share, stay up-to-date and grow their careers.
We strive for transparency and don't collect excess data.