Although what I'm about to talk about is well documented, I've never come across it in my 10 year career using Git. I stumbled across it out of sheer curiosity to see what would happen if I used a repository instead of a remote name. In theory Git would treat them the same, since everything is technically a ref, and it did. The idea is simply to be able to push your code anywhere, without having to first add the remote to your local repository. You're probably asking why you would want to do this, or why anyone would even care that this is possible. I have a few use cases below which are now way easier day to day.
A few weeks ago I decided to take the leap and implement Webpacker into an existing Rails project. Initially this seemed like a great idea and almost too easy thanks to the rails/webpacker project. After a couple of hours I had everything working and some existing React components migrated from a custom compile system to the asset pipeline. Deploying to staging had a few minor hiccups, but nothing major and the project was ready for sign-off and production release.