There are the following requirement types:

The <packages> section lists CMSIS Packs that have been used to configure the project. This includes the specification of a version range to ensure compatibility. If no version is provided, the latest installed version is used. If not yet installed, the latest available version will be installed before resolving the configuration.
The <compilers> section specifies the toolchains that are supported by this example. The required compiler version is specified using the version element. If no compiler is specified, it is assumed that any toolchain will work.
The <languages> section allows to specify requirements regarding the programming language, for example C99 standard. If no language requirements are set, ANSI C is assumed.
The <targets> section allows to specify requirements regarding the device or device series. If no target requirements are set, the pack is listed as generic that works with any device, board, or processor.

Example requirements section:

<package xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="PACK.xsd"/>
  ...
  <requirements>
    <packages>
      <package name="STM32F4xx_DFP" vendor="Keil" version="2.8.0:2.8.0"/>
    </packages>
    <compilers>
      <compiler name="ARMCC" version="5.0.0:5.99.0"/>
    </compilers>
    <languages>
      <language name="C" version="99"/>
    </languages>
  </requirements>
  ...
</package>

/requirements

Parents	Element Chain
package	/package
Attributes	Description	Type	Use
Child Elements	Description	Type	Occurrence
packages	List of software packs required for the project to build.	PackagesType	<0..1>
compilers	List of compilers required for the project to build. Support for all compilers is assumed when not specified.	CompilersType	<0..1>
languages	List of language standards required for the project to build. Assuming ANSI C if not set.	LanguagesType	<0..1>
targets	Restrict a software pack to a list of devices, boards, or processor cores that are supported.	TargetsType	<0..1>

/package/requirements/packages

Example packages section:

<package xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="PACK.xsd"/>
  ...
  <requirements>
    <packages>
      <package name="STM32F4xx_DFP" vendor="Keil" version="2.8.0:2.8.0"/>
    </packages>
  </requirements>
  ...
</package>

/package

Parents	Element Chain
packages	/package/requirements/packages
Attributes	Description	Type	Use
vendor	specify vendor of the package (e.g. "ARM")	RestrictedString	required
name	Name of the pack	RestrictedString	required
version	Version of the required software pack which can be: Minimum version (higher versions are accepted). Version range specified with min_version:max_version. min_version must be lower or equal than max_version. If min_version and max_version are equal, the version must match. If no version is specified, the latest available version is assumed.	VersionType	optional

/package/requirements/compilers

Example compilers section:

<package xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="PACK.xsd"/>
  ...
  <requirements>
    <compilers>
      <compiler name="ARMCC" version="5.0.0:5.99.0"/>
    </compilers>
  </requirements>
  ...
</package>

/compiler

Parents	Element Chain
requirements	element_requirements
Attributes	Description	Type	Use
name	Name of the required compiler (i.e. "ARMCC", "IAR")	CompilerEnumType	required
version	Version of the required compiler which can be: Minimum version (higher versions are accepted). Version range specified with min_version:max_version. min_version must be lower or equal than max_version. If min_version and max_version are equal, the version must match.	VersionType	required

/package/requirements/languages

Example languages section:

<package xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="PACK.xsd"/>
  ...
  <requirements>
    <languages>
      <language name="C" version="99"/>
    <languages>
  </requirements>
  ...
</package>

/language

Parents	Element Chain
requirements	element_requirements
Attributes	Description	Type	Use
name	Name of the programming language (i.e. "C", "C++")	xs:string	required
version	Version of the language standard (i.e. 90, 99, etc.). The setting will be reflected in the compiler commandline.	xs:string	required

/package/requirements/targets

The targets section marks a pack device specific. Multiple targets can be listed to allow usage for several devices or device series. The indented usage is for installers and web pages to show packs only for specific devices.

It allows also to specify boards and processor cores, as overtime this element may simplify conditions. However, currently it has no impact on the selection of pack content such as components. Therefore these attributes are experimental.

Example targets section:

<package xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="PACK.xsd"/>
  ...
  <requirements>
    <targets>
      <target Dvendor="STMicroelectronics:13" Dname="STM32H7*"/>    <!-- supports STM32H7 device series -->
      <target Dvendor="STMicroelectronics:13" Dname="STM32U585"/>   <!-- and supports STM32U585 device -->
    </targets>
  </requirements>
  ...
</package>

/target

Parents	Element Chain
targets	/package/requirements/targets
Attributes	Description	Type	Use
Dvendor	Specifies the silicon vendor of the device	xs:string	optional
Dname	Specifies the name of the device (wildcards possible)	xs:string	optional
Dcore	Specifies a processor core (experimental)	xs:string	optional
Bvendor	Specifies the board vendor (experimental)	xs:string	optional
Bname	Specifies the board name (experimental)	xs:string	optional
Brevision	Specifies the board revision (experimental)	xs:string	optional