You can use Pharo with git and github outside the box if you are using MacOS or Linux, there are some issues I think with Windows. Pharo uses Filetree which export source to files and makes commits , pulls , pushs etc. Gitfiletree allows filetree to be managed by git from inside Pharo without the use of a terminal but you can still use the terminal if that is your thing. I explain filetree, git and github in this video
Incidentally, even back in the day with the original Smalltalk-80 the "source" was available in a plain text sources file and the programmer's changes and additions were available in a plain text changes file which were in-sync with the image file.
Of course, arbitrary code could be exported in text files from the "binary image" file (even if that required code to be de-compiled from bytecode to text).
The source still is available as source code, so tools can work with that. The standard in the Smalltalk world is Monticello, I hope they added good tooling around it (the implementation I've seen was painful if you had ever used mercurial, git or even SVN, but I don't know how things are with Pharo)
https://www.youtube.com/watch?v=n2WNYDtO0cE&list=PLqbtQ7OkSt...