5. Creating and saving a definition
Contents of DED 0.2
When a user creates a document of a designer type, the host MUST write the envelope first, with ded the version of DED it writes and designer the designer type's origin, and then the designer type's content, as the template of the binding chosen for the file (FBL section 13) gives it. A Markdown definition MUST be written with 0.2 or a later version, since DED 0.1 does not state its envelope.
The envelope is written when the definition is created and changed by nobody afterwards: no operation of a designer type (DESL section 8) can set it, and saving a definition (DESL section 10.4) leaves its bytes as they are.
The JSON form of a definition MAY have the extension .ded; a designer type whose JSON binding claims .ded reads it as it reads its .json files.