The “plain” encoding represents a zettel the same way it is stored in a file with an extension [`.zettel`](00001005000000).

Zettel with a [syntax](00001006020000#syntax) value [“zmk”](00001008000000#zmk) are typically stored in a file with the extension `.zettel`.
Storing zettel with other syntax values in a `.zettel` file is also possible, but not recommended.
In those cases, the zettel is stored in two files: one file (without a filename extension) contains the metadata, and the other stores the zettel content.

These two cases are mirrored by specifying the required [part](00001012920800) of a zettel:

* If part has the value “zettel”, the full zettel, both metadata and content, is encoded.
  This corresponds to storing a zettel in a single file with the extension `.zettel`.
* A part value of “meta” encodes only the metadata of a zettel.
* A part value of “content” (the default) encodes the raw content of a zettel.

If transferred via HTTP, the content type depends on the selected part:

* If part has the value “zettel”, the content type is either `application/octet-stream` (for binary content) or a value derived from the `syntax` metadata.
* A part value of “content” results in a content type is derived from the `syntax` metadata.
* A part value of “meta” results in a content type `text/plain; charset=utf-8`.