I'm working on a project which used the Facebook-maintained "python-sdk" project, previously found at https://github.com/facebook/python-sdk. It's now gone -- Facebook deleted the public repository.
Here's the bug report: https://developers.facebook.com/bugs/200182333402545/. Note the tag for "90-day breaking change": Facebook has some sort of policy that they give 90 days' notice for breaking API changes. I guess this doesn't count? There's a developer response where they basically say "We don't have this anymore" with no explanation.
The problem with deleting your repository off Github is that lots of people specify Github repositories in requirements.txt files. Requirements files are a Python Pip feature which lets you specify a list of dependencies for your code, to be auto-installed from the internet when needed. I had Facebook's python-sdk repository in my requirements file, and it's now gone, so I can't install its dependencies -- a deployment step (!).
Edit: Someone is maintaining the code at https://github.com/pythonforfacebook/facebook-sdk/.
(Previously, I advertised my own fork of the repository on Bitbucket, as last I pulled from it. So if you need it, feel free to point to mine: https://bitbucket.org/lincolnq/python-facebook-sdk/. But I'm probably not going to try and maintain it.)
Edit 2: Ha! Facebook did announce that they were discontinuing it. But (to quote Hitchhiker's Guide) it was "on display in the bottom of a locked filing cabinet stuck in a disused lavatory with a sign on the door saying 'Beware of the Leopard'." Check it out.
See discussion on Hacker News.