What is inside an AVRO file?

In the Hadoop world, one may encounter AVRO files quite often. AVRO file can be used in more or less the same way as text files. They can be read, stored and written out. However, the AVRO files are binary files that make them difficult to read. However, help is there. I downloaded the avro-tools-1.8.2.jar from http://apache.cs.uu.nl/avro/avro-1.8.2/java/. See: avro-tools-1.8.2.jar.
This opens the possibility to investigate what is inside an AVRO file. Let us assume, we have this AVRO file data.avro. Next commands provides an overview of the possibilities:

java -jar avro-tools-1.8.2.jar

Then, the avro file is written to a json file:

java -jar avro-tools-1.8.2.jar tojson data.avro

or the scheme is provides with:

java -jar avro-tools-1.8.2.jar getschema data.avro