Please note that these documents apply to OpenShift Online v2 only (accounts created before August 1st, 2016).
If you are using one of the OpenShift 3 products, please refer to documents available at

Tomcat Template Repository Layout

webapps/           Location for built WARs (details below)
src/               Example Maven source structure
pom.xml            Example Maven build file
.openshift/        Location for OpenShift specific files
    config/          Location for configuration files such as server.xml
    action_hooks/    See the Action Hooks documentation (1)
    markers/         See the Markers section below (2)
1 Action Hooks documentation
2 Markers