Comment by NateDad

"it makes a local copy of that external library. And if you have a local copy, you can edit it. And meanwhile, that person you copied the OpenGL code from? They are also changing their version (fixing bugs, adding features, adding bugs). Therefore there is no guarantee that your version and their version remain compatible: it takes work to maintain compatibility."

Remote packages in Go are like DLLs for other languages. Yes, if you edit a DLL locally, and other people download the public version of that DLL, they won't be the same. DON'T DO THAT.

Make your own copy of the public Go repository, so you can merge in changes from the main branch as you see fit. This is akin to making a copy of the DLL and using that to distribute with your code, rather than just telling people "go download the newest version of the DLL from github".

It's also good practice for go authors to keep any one repository backwards compatible, make it clear when the code is in flux and may have breaking changes... and to make new branches if they have to make significant changes to their code.