When YAML files are located in the directory configured by magnolia.bootstrap.dir, this content is not bootstrapped.

Steps to reproduce ( in a new Magnolia bundle):

1. In an already working instance, create a page and export it to YAML (for example, with a page it might be any other content).
2. Store the YAML file in /bootstrap/common (magnolia.bootstrap.dir default value) in the new instance.
3. Start the server and install Magnolia.
4. Go to Pages app, the page wasn't bootstrapped.

The cause seems to be in info.magnolia.importexport.Bootstrapper.getBootstrapFiles(String[], String, BootstrapFilter) where YAML files are not accepted:

public boolean accept(File dir, String name) {
                    return name.startsWith(repositoryName + ".")
                            && filter.accept(name)
                            && (name.endsWith(DataTransporter.XML) || name.endsWith(DataTransporter.ZIP) || name
                            .endsWith(DataTransporter.GZ) || name.endsWith(DataTransporter.PROPERTIES));
                }