This is native Android TorService built on the Tor shared library built for Android. The included libtor.so binaries can also be used directly as a tor daemon. Binaries are available on Maven Central:

dependencies {
    implementation 'info.guardianproject:tor-android:0.4.6.10'
    implementation 'info.guardianproject:jtorctl:0.4.5.7'
}

Tor protects your privacy on the internet by hiding the connection between your Internet address and the services you use. We believe Tor is reasonably secure, but please ensure you read the instructions and configure it properly. Learn more at https://torproject.org/

• https://2019.www.torproject.org/docs/faq
• https://support.torproject.org/faq/

Please see: https://raw.githubusercontent.com/guardianproject/tor-android/master/BUILD

This can be built reproducibly using the included Vagrant VM setup. That will run with either libvirt or VirtualBox. The provisioning is based on the "release" job in .gitlab-ci.yml.