Title: Classes | Page 2 of 17 | Developer.WordPress.org

---

# Classes

 * class[Http](https://developer.wordpress.org/reference/classes/wporg-requests-exception-http/)
 * Exception based on HTTP response
 * Used by [0 functions](https://developer.wordpress.org/reference/classes/wporg-requests-exception-http/#used-by)
   | Uses [0 functions](https://developer.wordpress.org/reference/classes/wporg-requests-exception-http/#uses)
   | Source: [wp-includes/Requests/src/Exception/Http.php:18](https://github.com/WordPress/wordpress-develop/blob/6.9.4/src/wp-includes/Requests/src/Exception/Http.php#L18-L78)
 * class[IdnaEncoder](https://developer.wordpress.org/reference/classes/wporg-requests-idnaencoder/)
 * IDNA URL encoder
 * Used by [0 functions](https://developer.wordpress.org/reference/classes/wporg-requests-idnaencoder/#used-by)
   | Uses [0 functions](https://developer.wordpress.org/reference/classes/wporg-requests-idnaencoder/#uses)
   | Source: [wp-includes/Requests/src/IdnaEncoder.php:19](https://github.com/WordPress/wordpress-develop/blob/6.9.4/src/wp-includes/Requests/src/IdnaEncoder.php#L19-L412)
 * class[InputValidator](https://developer.wordpress.org/reference/classes/wporg-requests-utility-inputvalidator/)
 * Input validation utilities.
 * Used by [0 functions](https://developer.wordpress.org/reference/classes/wporg-requests-utility-inputvalidator/#used-by)
   | Uses [0 functions](https://developer.wordpress.org/reference/classes/wporg-requests-utility-inputvalidator/#uses)
   | Source: [wp-includes/Requests/src/Utility/InputValidator.php:19](https://github.com/WordPress/wordpress-develop/blob/6.9.4/src/wp-includes/Requests/src/Utility/InputValidator.php#L19-L109)
 * class[InvalidArgument](https://developer.wordpress.org/reference/classes/wporg-requests-exception-invalidargument/)
 * Exception for an invalid argument passed.
 * Used by [0 functions](https://developer.wordpress.org/reference/classes/wporg-requests-exception-invalidargument/#used-by)
   | Uses [0 functions](https://developer.wordpress.org/reference/classes/wporg-requests-exception-invalidargument/#uses)
   | Source: [wp-includes/Requests/src/Exception/InvalidArgument.php:13](https://github.com/WordPress/wordpress-develop/blob/6.9.4/src/wp-includes/Requests/src/Exception/InvalidArgument.php#L13-L41)
 * class[Ipv6](https://developer.wordpress.org/reference/classes/wporg-requests-ipv6/)
 * Class to validate and to work with IPv6 addresses
 * Used by [0 functions](https://developer.wordpress.org/reference/classes/wporg-requests-ipv6/#used-by)
   | Uses [0 functions](https://developer.wordpress.org/reference/classes/wporg-requests-ipv6/#uses)
   | Source: [wp-includes/Requests/src/Ipv6.php:21](https://github.com/WordPress/wordpress-develop/blob/6.9.4/src/wp-includes/Requests/src/Ipv6.php#L21-L203)
 * class[Iri](https://developer.wordpress.org/reference/classes/wporg-requests-iri/)
 * IRI parser/serialiser/normaliser
 * Used by [0 functions](https://developer.wordpress.org/reference/classes/wporg-requests-iri/#used-by)
   | Uses [0 functions](https://developer.wordpress.org/reference/classes/wporg-requests-iri/#uses)
   | Source: [wp-includes/Requests/src/Iri.php:72](https://github.com/WordPress/wordpress-develop/blob/6.9.4/src/wp-includes/Requests/src/Iri.php#L72-L1116)
 * class[IXR_Base64](https://developer.wordpress.org/reference/classes/ixr_base64/)
 * IXR_Base64
 * Used by [0 functions](https://developer.wordpress.org/reference/classes/ixr_base64/#used-by)
   | Uses [0 functions](https://developer.wordpress.org/reference/classes/ixr_base64/#uses)
   | Source: [wp-includes/IXR/class-IXR-base64.php:9](https://github.com/WordPress/wordpress-develop/blob/6.9.4/src/wp-includes/IXR/class-IXR-base64.php#L9-L32)
 * class[IXR_Client](https://developer.wordpress.org/reference/classes/ixr_client/)
 * IXR_Client
 * Used by [2 functions](https://developer.wordpress.org/reference/classes/ixr_client/#used-by)
   | Uses [0 functions](https://developer.wordpress.org/reference/classes/ixr_client/#uses)
   | Source: [wp-includes/IXR/class-IXR-client.php:10](https://github.com/WordPress/wordpress-develop/blob/6.9.4/src/wp-includes/IXR/class-IXR-client.php#L10-L172)
 * class[IXR_ClientMulticall](https://developer.wordpress.org/reference/classes/ixr_clientmulticall/)
 * IXR_ClientMulticall
 * Used by [0 functions](https://developer.wordpress.org/reference/classes/ixr_clientmulticall/#used-by)
   | Uses [1 function](https://developer.wordpress.org/reference/classes/ixr_clientmulticall/#uses)
   | Source: [wp-includes/IXR/class-IXR-clientmulticall.php:8](https://github.com/WordPress/wordpress-develop/blob/6.9.4/src/wp-includes/IXR/class-IXR-clientmulticall.php#L8-L55)
 * class[IXR_Date](https://developer.wordpress.org/reference/classes/ixr_date/)
 * IXR_Date
 * Used by [0 functions](https://developer.wordpress.org/reference/classes/ixr_date/#used-by)
   | Uses [0 functions](https://developer.wordpress.org/reference/classes/ixr_date/#uses)
   | Source: [wp-includes/IXR/class-IXR-date.php:9](https://github.com/WordPress/wordpress-develop/blob/6.9.4/src/wp-includes/IXR/class-IXR-date.php#L9-L74)
 * class[IXR_Error](https://developer.wordpress.org/reference/classes/ixr_error/)
 * IXR_Error
 * Used by [0 functions](https://developer.wordpress.org/reference/classes/ixr_error/#used-by)
   | Uses [0 functions](https://developer.wordpress.org/reference/classes/ixr_error/#uses)
   | Source: [wp-includes/IXR/class-IXR-error.php:9](https://github.com/WordPress/wordpress-develop/blob/6.9.4/src/wp-includes/IXR/class-IXR-error.php#L9-L53)
 * class[IXR_IntrospectionServer](https://developer.wordpress.org/reference/classes/ixr_introspectionserver/)
 * IXR_IntrospectionServer
 * Used by [0 functions](https://developer.wordpress.org/reference/classes/ixr_introspectionserver/#used-by)
   | Uses [1 function](https://developer.wordpress.org/reference/classes/ixr_introspectionserver/#uses)
   | Source: [wp-includes/IXR/class-IXR-introspectionserver.php:9](https://github.com/WordPress/wordpress-develop/blob/6.9.4/src/wp-includes/IXR/class-IXR-introspectionserver.php#L9-L174)
 * class[IXR_Message](https://developer.wordpress.org/reference/classes/ixr_message/)
 * IXR_MESSAGE
 * Used by [0 functions](https://developer.wordpress.org/reference/classes/ixr_message/#used-by)
   | Uses [0 functions](https://developer.wordpress.org/reference/classes/ixr_message/#uses)
   | Source: [wp-includes/IXR/class-IXR-message.php:10](https://github.com/WordPress/wordpress-develop/blob/6.9.4/src/wp-includes/IXR/class-IXR-message.php#L10-L247)
 * class[IXR_Request](https://developer.wordpress.org/reference/classes/ixr_request/)
 * IXR_Request
 * Used by [0 functions](https://developer.wordpress.org/reference/classes/ixr_request/#used-by)
   | Uses [0 functions](https://developer.wordpress.org/reference/classes/ixr_request/#uses)
   | Source: [wp-includes/IXR/class-IXR-request.php:9](https://github.com/WordPress/wordpress-develop/blob/6.9.4/src/wp-includes/IXR/class-IXR-request.php#L9-L54)
 * class[IXR_Server](https://developer.wordpress.org/reference/classes/ixr_server/)
 * IXR_Server
 * Used by [2 functions](https://developer.wordpress.org/reference/classes/ixr_server/#used-by)
   | Uses [0 functions](https://developer.wordpress.org/reference/classes/ixr_server/#uses)
   | Source: [wp-includes/IXR/class-IXR-server.php:9](https://github.com/WordPress/wordpress-develop/blob/6.9.4/src/wp-includes/IXR/class-IXR-server.php#L9-L220)
 * class[IXR_Value](https://developer.wordpress.org/reference/classes/ixr_value/)
 * IXR_Value
 * Used by [0 functions](https://developer.wordpress.org/reference/classes/ixr_value/#used-by)
   | Uses [0 functions](https://developer.wordpress.org/reference/classes/ixr_value/#uses)
   | Source: [wp-includes/IXR/class-IXR-value.php:8](https://github.com/WordPress/wordpress-develop/blob/6.9.4/src/wp-includes/IXR/class-IXR-value.php#L8-L138)
 * class[Jar](https://developer.wordpress.org/reference/classes/wporg-requests-cookie-jar/)
 * Cookie holder object
 * Used by [0 functions](https://developer.wordpress.org/reference/classes/wporg-requests-cookie-jar/#used-by)
   | Uses [0 functions](https://developer.wordpress.org/reference/classes/wporg-requests-cookie-jar/#uses)
   | Source: [wp-includes/Requests/src/Cookie/Jar.php:26](https://github.com/WordPress/wordpress-develop/blob/6.9.4/src/wp-includes/Requests/src/Cookie/Jar.php#L26-L187)
 * class[Language_Pack_Upgrader](https://developer.wordpress.org/reference/classes/language_pack_upgrader/)
 * Core class used for updating/installing language packs (translations) for plugins,
   themes, and core.
 * Used by [0 functions](https://developer.wordpress.org/reference/classes/language_pack_upgrader/#used-by)
   | Uses [1 function](https://developer.wordpress.org/reference/classes/language_pack_upgrader/#uses)
   | Source: [wp-admin/includes/class-language-pack-upgrader.php:19](https://github.com/WordPress/wordpress-develop/blob/6.9.4/src/wp-admin/includes/class-language-pack-upgrader.php#L19-L487)
 * class[Language_Pack_Upgrader_Skin](https://developer.wordpress.org/reference/classes/language_pack_upgrader_skin/)
 * Translation Upgrader Skin for WordPress Translation Upgrades.
 * Used by [0 functions](https://developer.wordpress.org/reference/classes/language_pack_upgrader_skin/#used-by)
   | Uses [1 function](https://developer.wordpress.org/reference/classes/language_pack_upgrader_skin/#uses)
   | Source: [wp-admin/includes/class-language-pack-upgrader-skin.php:18](https://github.com/WordPress/wordpress-develop/blob/6.9.4/src/wp-admin/includes/class-language-pack-upgrader-skin.php#L18-L115)
 * class[MagpieRSS](https://developer.wordpress.org/reference/classes/magpierss/)
 * Used by [0 functions](https://developer.wordpress.org/reference/classes/magpierss/#used-by)
   | Uses [0 functions](https://developer.wordpress.org/reference/classes/magpierss/#uses)
   | Source: [wp-includes/rss.php:34](https://github.com/WordPress/wordpress-develop/blob/6.9.4/src/wp-includes/rss.php#L34-L399)
 * class[MO](https://developer.wordpress.org/reference/classes/mo/)
 * Used by [0 functions](https://developer.wordpress.org/reference/classes/mo/#used-by)
   | Uses [1 function](https://developer.wordpress.org/reference/classes/mo/#uses)
   | Source: [wp-includes/pomo/mo.php:14](https://github.com/WordPress/wordpress-develop/blob/6.9.4/src/wp-includes/pomo/mo.php#L14-L353)
 * class[NOOP_Translations](https://developer.wordpress.org/reference/classes/noop_translations/)
 * Used by [0 functions](https://developer.wordpress.org/reference/classes/noop_translations/#used-by)
   | Uses [0 functions](https://developer.wordpress.org/reference/classes/noop_translations/#uses)
   | Source: [wp-includes/pomo/translations.php:418](https://github.com/WordPress/wordpress-develop/blob/6.9.4/src/wp-includes/pomo/translations.php#L418-L545)
 * class[Parser](https://developer.wordpress.org/reference/classes/avifinfo-parser/)
 * Used by [0 functions](https://developer.wordpress.org/reference/classes/avifinfo-parser/#used-by)
   | Uses [0 functions](https://developer.wordpress.org/reference/classes/avifinfo-parser/#uses)
   | Source: [wp-includes/class-avif-info.php:315](https://github.com/WordPress/wordpress-develop/blob/6.9.4/src/wp-includes/class-avif-info.php#L315-L781)
 * class[Plugin_Installer_Skin](https://developer.wordpress.org/reference/classes/plugin_installer_skin/)
 * Plugin Installer Skin for WordPress Plugin Installer.
 * Used by [0 functions](https://developer.wordpress.org/reference/classes/plugin_installer_skin/#used-by)
   | Uses [1 function](https://developer.wordpress.org/reference/classes/plugin_installer_skin/#uses)
   | Source: [wp-admin/includes/class-plugin-installer-skin.php:18](https://github.com/WordPress/wordpress-develop/blob/6.9.4/src/wp-admin/includes/class-plugin-installer-skin.php#L18-L355)
 * class[Plugin_Upgrader](https://developer.wordpress.org/reference/classes/plugin_upgrader/)
 * Core class used for upgrading/installing plugins.
 * Used by [0 functions](https://developer.wordpress.org/reference/classes/plugin_upgrader/#used-by)
   | Uses [1 function](https://developer.wordpress.org/reference/classes/plugin_upgrader/#uses)
   | Source: [wp-admin/includes/class-plugin-upgrader.php:21](https://github.com/WordPress/wordpress-develop/blob/6.9.4/src/wp-admin/includes/class-plugin-upgrader.php#L21-L710)
 * class[Plugin_Upgrader_Skin](https://developer.wordpress.org/reference/classes/plugin_upgrader_skin/)
 * Plugin Upgrader Skin for WordPress Plugin Upgrades.
 * Used by [0 functions](https://developer.wordpress.org/reference/classes/plugin_upgrader_skin/#used-by)
   | Uses [1 function](https://developer.wordpress.org/reference/classes/plugin_upgrader_skin/#uses)
   | Source: [wp-admin/includes/class-plugin-upgrader-skin.php:18](https://github.com/WordPress/wordpress-develop/blob/6.9.4/src/wp-admin/includes/class-plugin-upgrader-skin.php#L18-L123)
 * class[Plural_Forms](https://developer.wordpress.org/reference/classes/plural_forms/)
 * Used by [0 functions](https://developer.wordpress.org/reference/classes/plural_forms/#used-by)
   | Uses [0 functions](https://developer.wordpress.org/reference/classes/plural_forms/#uses)
   | Source: [wp-includes/pomo/plural-forms.php:10](https://github.com/WordPress/wordpress-develop/blob/6.9.4/src/wp-includes/pomo/plural-forms.php#L10-L350)
 * class[PO](https://developer.wordpress.org/reference/classes/po/)
 * Used by [0 functions](https://developer.wordpress.org/reference/classes/po/#used-by)
   | Uses [1 function](https://developer.wordpress.org/reference/classes/po/#uses)
   | Source: [wp-includes/pomo/po.php:30](https://github.com/WordPress/wordpress-develop/blob/6.9.4/src/wp-includes/pomo/po.php#L30-L516)
 * class[POMO_CachedFileReader](https://developer.wordpress.org/reference/classes/pomo_cachedfilereader/)
 * Reads the contents of the file in the beginning.
 * Used by [1 function](https://developer.wordpress.org/reference/classes/pomo_cachedfilereader/#used-by)
   | Uses [1 function](https://developer.wordpress.org/reference/classes/pomo_cachedfilereader/#uses)
   | Source: [wp-includes/pomo/streams.php:309](https://github.com/WordPress/wordpress-develop/blob/6.9.4/src/wp-includes/pomo/streams.php#L309-L333)
 * class[POMO_CachedIntFileReader](https://developer.wordpress.org/reference/classes/pomo_cachedintfilereader/)
 * Reads the contents of the file in the beginning.
 * Used by [0 functions](https://developer.wordpress.org/reference/classes/pomo_cachedintfilereader/#used-by)
   | Uses [1 function](https://developer.wordpress.org/reference/classes/pomo_cachedintfilereader/#uses)
   | Source: [wp-includes/pomo/streams.php:340](https://github.com/WordPress/wordpress-develop/blob/6.9.4/src/wp-includes/pomo/streams.php#L340-L359)

 [Previous Page](https://developer.wordpress.org/reference/classes/?output_format=md)

[1](https://developer.wordpress.org/reference/classes/?output_format=md) 2 [3](https://developer.wordpress.org/reference/classes/page/3/?output_format=md)
[4](https://developer.wordpress.org/reference/classes/page/4/?output_format=md) …
[17](https://developer.wordpress.org/reference/classes/page/17/?output_format=md)

 [Next Page](https://developer.wordpress.org/reference/classes/page/3/?output_format=md)