It seems that jenkins_2.107.3_all.deb no longer has an explicit dependency on default-jre-headless or java8-runtime-headless, which means jenkins installations are easily broken if "apt-get autoremove" is run (and it's generally good practice for debian/ubuntu admins to run this command periodically).

jenkins_2.107.2_all.deb and earlier had the correct dependency.

There is a comment on https://pkg.jenkins.io/debian/ which suggests that this is intentional:

You will need to explicitly install a Java runtime environment, because Jenkins does not work with Java 9, this is the safest way to ensure your system ends properly configured. Adding an explicit dependency requirement on Java could force installation of undesired versions of the JVM. Check JENKINS-40689 for more details about Jenkins and Java 9 compatibility.

 ...but this seems wrong- the package should just depend on java8 packages specifically.