A message bundle (resource bundle in Java) is a collection of
.properties files. Each file contains key-value pairs of translated user interface text such as labels and messages. The keys in all files of the same bundle are identical but the values are language specific translations.
A message bundle must contain at least one
.properties file. The files are named after the language (locale):
<bundle-name>_<locale>.properties, for example
app-pages-messages_en.properties. Every Magnolia module should provide its own message bundle. If a module installs several apps, each app should have its own message bundle.