Tree
A Tree in data structure is a Partially ordered set. From a programming viewpoint, all data types are some form of Tree, and therefore, has been explicitly utilized to perform all possible programming tasks. However, due to various engineering tricks, program text has been organized in many ways, but it is necessary to note that they are all trees. More importantly, they should have have some kind of underlying Abstract syntax tree.
Example
The most relevant example of tree-based data representations are: XML, JSON, and YAML. These tree-based data representations have evolved for a long time, and they have been adopted broadly by many industrial applications.
The key idea is the all these data representations should be isomorphic and can find automatic translation between these data representation mechanisms[1]. More specifically, it is known that YAML can always be losslessly converted to JSON[2]