SCM Backup is a tool which makes offline backups of your cloud hosted source code repositories, by cloning them. It supports backing up from multiple source code hosters and backing up multiple users/teams per source code hoster.
At the moment, the following hosters are supported:
And it's written in .NET Core, which means that it's supposed to run on Windows, Linux and MacOS.
SCM Backup is licensed under the GNU GPLv3.