This extension is a metapackages which includes all bootstrap components for Contao CMS.
See changelog
Bootstrap for Contao is prepared for the Contao Managed Edition. It's pretty simple to install the package. Just search for the package in the Contao Manager and install it. Alternatively you can use the CLI.
# Using the contao manager
$ php contao-manager.phar.php composer require contao-bootstrap/bundle~2.1
# Using composer directly
$ php composer.phar require contao-bootstrap/bundle~2.1