FormatVersion defines the version of the TSCN file format Snippet from the C++ code: https://github.com/godotengine/godot/blob/master/scene/resources/resource_format_text.cpp#L39.

Connection connects a Signal From a node To another node and calls its Method.

Editable marks an instanced scene as editable, which means you can edit its child nodes.

ExtResource is a link to resources not contained within the TSCN file itself Documentation: https://docs.godotengine.org/en/stable/development/file_formats/tscn.html#external-resources.

Import is the configuration of well Godot imports (*.import file).

KeyValuePair a pair which contains a value with its associated key.

MetaData contains extra informations obtained from parsing.

Node is Godots central building block.

Project is a data model for your project.godot files.

Resource is the model for a .tres file.

Scene is the data representation of a Godot TSCN Scene, which contains resources and a node tree.

SubResource a TSCN file can contain meshes, materials and other data which are contained within this type Documentation: https://docs.godotengine.org/en/stable/development/file_formats/tscn.html#internal-resources.

Type represents more or less something akin to a struct in TSCN files, for instance a Vector.

Value is a wrapper for a regular TSCN value which also contains meta data.