The C4P file is a basic xml file.

<c4p>
 <applications>
...
 </applications>
</c4p>

Within the file you will have the following tags or sections:

AutoRun -- C4Id

<autorun="..." />

This specified the <app> section in this c4p file that should be autoselected to install when the c4p file is initial parsed. It is implied if the c4p file contains only one <app> section. If a c4p file contains more than one <app> section and no autorun then no automatic selection occurs.

App C4Id

<app appid="..."> ... </app> [required]

This is the C4 application id. It can be used to query C4 to retrieve the data for this application. It must be immutable and never reused after an application is deleted (otherwise there's the risk that a client using that id gets the wrong application).

the App can contain at most 1 [AppProfile|c4p_c4dataapplication], 0 or more [InstallProfiles|c4p_installprofile] and 0 or more CdProfiles

CxVersion -- list of (product, version) pairs

<app> <cxversion product="..."> </cxversion> [required]

This is used to filter applications from a c4p file to be sure only the profiles designed for the given product are displayed. This allows a given c4p file to have multiple entries for a given AppId target at different products and versions. The product is generally either "cxoffice" or "cxgames" but specialized products are possible. Version is in the X.X* form. CrossOver does matches as close as possible. so if "9.0.1" is given it will match "9.0.1" but not "9.0.2". If "9.0" is given it will match both "9.0.1" and "9.0.2". Just using "9" is invalid, the minimum string is X.X

Name -- localizable string

<app> <name> </name> [required]

This is the same application name used on the C4 website. It needs to be localizable because some applications have a different name in each language (for instance Windows Media Player). Also it should match the application's Windows display name (as specified in the uninstaller key).

Description -- localizable limited HTML string

<app> <description> </description> [required]

The same description as in the C4 website. It should be short, a few lines, with possibly some simple HTML.