bash-static is a package found on some Linux distributions that provides a static-linked bash shell.
This is useful for system recovery purposes.
The root user should probably have a static-linked shell as their default shell.
Static-linked shells can also be distributed with software that uses specific functionality provided by a particular version to ensure that they run as intendended on the target host.
https://unix.stackexchange.com/questions/387294/what-is-bash-static-used-for