Matthew Casperson's blog post from May 6, 2020, explores how to configure a Tomcat Docker image to enable the manager application for Java deployments. The process involves defining a Tomcat user with necessary roles in the tomcat-users.xml file and modifying the context.xml file to disable network filtering, allowing external traffic. Since the default Tomcat Docker image does not load applications by default, users must move the default applications from /usr/local/tomcat/webapps.dist to /usr/local/tomcat/webapps by overriding the Docker command. The post provides detailed instructions, including the necessary command and configuration files, to ensure Tomcat runs with a functional manager application, while clarifying that these default applications are not pre-loaded due to security precautions.