node_type_form in core/modules/node/node.types.inc

Form constructor for the node type editing form.

node_type_reset in core/modules/node/node.types.inc

Resets relevant fields of a module-defined node type to their default values.

node_type_save in core/modules/node/node.module

Saves a node type to the database.

_node_types_build in core/modules/node/node.module

Builds and returns the list of available node types.