The following cards are allowed on an attachment artifact:

<blockquote>
<b>A</b> <i>filename target</i> ?<i>source</i>?<br />
<b>C</b> <i>comment</i><br />
<b>D</b> <i>time-and-date-stamp</i><br />
<b>N</b> <i>mimetype</i><br />
<b>T</b> <b>+</b><i>tag-name</i> <b>*</b> ?<i>value</i>?<br />
<b>U</b> <i>user-name</i><br />
<b>Z</b> <i>checksum</i>
</blockquote>

The A card specifies a filename for the attachment in its first argument.
The second argument to the A card is the name of the wiki page or
ticket or technical note to which the attachment is connected.  The
third argument is either missing or else it is the 40-character artifact
ID of the attachment itself.  A missing third argument means that the
attachment should be deleted.

The C card is an optional comment describing what the attachment is about.
The C card is optional, but there can only be one.

A single D card is required to give the date and time when the attachment
was applied.

There may be zero or one N cards.  The N card specifies the mimetype of the
comment text provided in the C card.  If the N card is omitted, the C card
mimetype is taken to be text/plain.

An attachment might contain one or more T-cards used to set
[./branching.wiki#tags | tags or properties]
on the attachment.  The format of the T-card is the same as
described in [#ctrl | Control Artifacts] section above, except that the
second argument is the single character "<b>*</b>" instead of an
artifact ID and the name is always prefaced by "<b>+</b>".
The <b>*</b> in place of the artifact ID indicates that
the tag or property applies to the current artifact.  It is not
possible to encode the current artifact ID as part of an artifact,
since the act of inserting the artifact ID would change the artifact ID,
hence a <b>*</b> is used to represent "self".  The "<b>+</b>" on the
name means that tags can only be add and they can only be non-propagating
tags.  In an attachment, T cards are normally used to identify test
case results on check-ins.


A single U card gives the name of the user who added the attachment.
If an attachment is added anonymously, then the U card may be omitted.

The Z card is the usual checksum over the rest of the attachment artifact.
The Z card is required.