Note: this list is generated by pattern matching, so it may include some functions that are not actually implementations of this hook.

automated_cron_form_system_cron_settings_alter in core/modules/automated_cron/automated_cron.module
Implements hook_form_FORM_ID_alter() for the system_cron_settings() form.
block_form_form_test_alter_form_alter in core/modules/system/tests/modules/form_test/form_test.module
Implements hook_form_FORM_ID_alter().
book_form_node_confirm_form_alter in core/modules/book/book.module
Implements hook_form_BASE_FORM_ID_alter() for \Drupal\node\Form\NodeDeleteForm.
book_form_node_form_alter in core/modules/book/book.module
Implements hook_form_BASE_FORM_ID_alter() for \Drupal\node\NodeForm.
ckeditor5_form_filter_format_form_alter in core/modules/ckeditor5/ckeditor5.module
Implements hook_form_FORM_ID_alter().
ckeditor5_read_only_mode_form_node_page_form_alter in core/modules/ckeditor5/tests/modules/ckeditor5_read_only_mode/ckeditor5_read_only_mode.module
Implements hook_form_alter().
claro_form_media_form_alter in core/themes/claro/claro.theme
Implements hook_form_BASE_FORM_ID_alter() for \Drupal\media\MediaForm.
claro_form_media_library_add_form_alter in core/themes/claro/claro.theme
Implements hook_form_BASE_FORM_ID_alter().
claro_form_media_library_add_form_oembed_alter in core/themes/claro/claro.theme
Implements hook_form_FORM_ID_alter().
claro_form_media_library_add_form_upload_alter in core/themes/claro/claro.theme
Implements hook_form_FORM_ID_alter().
claro_form_menu_link_content_form_alter in core/themes/claro/claro.theme
Implements hook_form_BASE_FORM_ID_alter() for MenuLinkContentForm.
claro_form_menu_link_edit_alter in core/themes/claro/claro.theme
Implements hook_form_FORM_ID_alter() for MenuLinkEditForm.
claro_form_node_form_alter in core/themes/claro/claro.theme
Implements hook_form_BASE_FORM_ID_alter() for \Drupal\node\NodeForm.
claro_form_node_preview_form_select_alter in core/themes/claro/claro.theme
Implements hook_form_FORM_ID_alter().
claro_form_system_modules_alter in core/themes/claro/claro.theme
Implements hook_form_FORM_ID_alter() for the system_modules form.
claro_form_user_admin_permissions_alter in core/themes/claro/claro.theme
Implements hook_form_FORM_ID_alter() for the user_admin_permissions form.
claro_form_views_exposed_form_alter in core/themes/claro/claro.theme
Implements hook_form_FORM_ID_alter() for views_exposed_form.
claro_form_views_ui_add_handler_form_alter in core/themes/claro/claro.theme
Implements hook_form_FORM_ID_alter() for Views UI add handler form.
claro_form_views_ui_config_item_form_alter in core/themes/claro/claro.theme
Implements hook_form_FORM_ID_alter() for the Views UI config form.
claro_theme_suggestions_form_element_alter in core/themes/claro/claro.theme
Implements hook_theme_suggestions_HOOK_alter() for form_element.
comment_form_field_ui_display_overview_form_alter in core/modules/comment/comment.module
Implements hook_form_FORM_ID_alter().
comment_form_field_ui_field_storage_add_form_alter in core/modules/comment/comment.module
Implements hook_form_FORM_ID_alter() for field_ui_field_storage_add_form.
comment_form_field_ui_form_display_overview_form_alter in core/modules/comment/comment.module
Implements hook_form_FORM_ID_alter().
config_translation_test_form_config_translation_add_form_alter in core/modules/config_translation/tests/modules/config_translation_test/config_translation_test.module
Implements hook_form_FORM_ID_alter() for ConfigTranslationAddForm.
config_translation_test_form_config_translation_edit_form_alter in core/modules/config_translation/tests/modules/config_translation_test/config_translation_test.module
Implements hook_form_FORM_ID_alter() for ConfigTranslationEditForm.
config_translation_test_form_config_translation_form_alter in core/modules/config_translation/tests/modules/config_translation_test/config_translation_test.module
Implements hook_form_BASE_FORM_ID_alter() for ConfigTranslationFormBase.
contact_form_user_admin_settings_alter in core/modules/contact/contact.module
Implements hook_form_FORM_ID_alter().
contact_form_user_form_alter in core/modules/contact/contact.module
Implements hook_form_FORM_ID_alter().
contact_storage_test_form_contact_form_form_alter in core/modules/contact/tests/modules/contact_storage_test/contact_storage_test.module
Implements hook_form_FORM_ID_alter() for contact_form_form().
content_moderation_entity_form_display_alter in core/modules/content_moderation/content_moderation.module
Implements hook_entity_form_display_alter().
content_translation_form_field_config_edit_form_alter in core/modules/content_translation/content_translation.module
Implements hook_form_FORM_ID_alter() for 'field_config_edit_form'.
content_translation_form_language_content_settings_form_alter in core/modules/content_translation/content_translation.module
Implements hook_form_FORM_ID_alter() for language_content_settings_form().
content_translation_test_form_node_form_alter in core/modules/content_translation/tests/modules/content_translation_test/content_translation_test.module
Implements hook_form_BASE_FORM_ID_alter().
dblog_form_system_logging_settings_alter in core/modules/dblog/dblog.module
Implements hook_form_FORM_ID_alter() for system_logging_settings().
editor_form_filter_admin_overview_alter in core/modules/editor/editor.module
Implements hook_form_FORM_ID_alter().
editor_form_filter_format_form_alter in core/modules/editor/editor.module
Implements hook_form_BASE_FORM_ID_alter() for \Drupal\filter\FilterFormatEditForm.
entity_test_entity_form_display_alter in core/modules/system/tests/modules/entity_test/entity_test.module
Implements hook_entity_form_display_alter().
entity_test_entity_form_mode_alter in core/modules/system/tests/modules/entity_test/entity_test.module
Implements hook_entity_form_mode_alter().
entity_test_entity_form_mode_info_alter in core/modules/system/tests/modules/entity_test/entity_test.module
Implements hook_entity_form_mode_info_alter().
entity_test_form_entity_test_form_alter in core/modules/system/tests/modules/entity_test/entity_test.module
Implements hook_form_BASE_FORM_ID_alter().
entity_test_form_node_form_alter in core/modules/system/tests/modules/entity_test/entity_test.module
Implements hook_form_BASE_FORM_ID_alter().
field_form_config_admin_import_form_alter in core/modules/field/field.module
Implements hook_form_FORM_ID_alter().
field_ui_form_field_config_edit_form_alter in core/modules/field_ui/field_ui.module
Implements hook_form_FORM_ID_alter() for field_config_edit_form.
field_ui_form_field_ui_field_storage_add_form_alter in core/modules/field_ui/field_ui.module
Implements hook_form_FORM_ID_alter() for 'field_ui_field_storage_add_form'.
field_ui_test_deprecated_form_field_storage_config_edit_form_alter in core/modules/field_ui/tests/modules/field_ui_test_deprecated/field_ui_test_deprecated.module
Implements hook_form_FORM_ID_alter() for field_storage_config_edit_form.
field_ui_test_form_entity_view_display_edit_form_alter in core/modules/field_ui/tests/modules/field_ui_test/field_ui_test.module
Implements hook_form_FORM_BASE_ID_alter().
file_form_system_file_system_settings_alter in core/modules/file/file.module
Implements hook_form_FORM_ID_alter().
form_test_form_form_test_alter_form_alter in core/modules/system/tests/modules/form_test/form_test.module
Implements hook_form_FORM_ID_alter().
form_test_form_form_test_vertical_tabs_access_form_alter in core/modules/system/tests/modules/form_test/form_test.module
Implements hook_form_FORM_ID_alter() for form_test_vertical_tabs_access_form().
form_test_form_user_register_form_alter in core/modules/system/tests/modules/form_test/form_test.module
Implements hook_form_FORM_ID_alter() for the registration form.
forum_form_node_form_alter in core/modules/forum/forum.module
Implements hook_form_BASE_FORM_ID_alter() for \Drupal\node\NodeForm.
forum_form_taxonomy_term_form_alter in core/modules/forum/forum.module
Implements hook_form_FORM_ID_alter() for \Drupal\taxonomy\TermForm.
forum_form_taxonomy_vocabulary_form_alter in core/modules/forum/forum.module
Implements hook_form_BASE_FORM_ID_alter() for \Drupal\taxonomy\VocabularyForm.
inline_form_errors_element_info_alter in core/modules/inline_form_errors/inline_form_errors.module
Implements hook_element_info_alter().
layout_builder_entity_form_display_alter in core/modules/layout_builder/tests/modules/layout_builder_test/layout_builder_test.module
Implements hook_entity_form_display_alter().
layout_builder_form_entity_form_display_edit_form_alter in core/modules/layout_builder/layout_builder.module
Implements hook_form_FORM_ID_alter() for \Drupal\field_ui\Form\EntityFormDisplayEditForm.
layout_builder_test_form_layout_builder_configure_block_alter in core/modules/layout_builder/tests/modules/layout_builder_test/layout_builder_test.module
Implements hook_form_BASE_FORM_ID_alter() for layout_builder_configure_block.
layout_builder_test_form_layout_builder_configure_section_alter in core/modules/layout_builder/tests/modules/layout_builder_test/layout_builder_test.module
Implements hook_form_BASE_FORM_ID_alter() for layout_builder_configure_section.
locale_form_language_admin_add_form_alter in core/modules/locale/locale.module
Implements hook_form_FORM_ID_alter() for language_admin_add_form().
locale_form_language_admin_edit_form_alter in core/modules/locale/locale.module
Implements hook_form_FORM_ID_alter() for language_admin_edit_form().
locale_form_language_admin_overview_form_alter in core/modules/locale/locale.module
Implements hook_form_FORM_ID_alter() for language_admin_overview_form().
locale_form_system_file_system_settings_alter in core/modules/locale/locale.module
Implements hook_form_FORM_ID_alter() for system_file_system_settings().
media_form_field_ui_field_storage_add_form_alter in core/modules/media/media.module
Implements hook_form_FORM_ID_alter().
media_form_filter_format_add_form_alter in core/modules/media/media.module
Implements hook_form_FORM_ID_alter().
media_form_filter_format_edit_form_alter in core/modules/media/media.module
Implements hook_form_FORM_ID_alter().
media_library_form_overwrite_test_media_source_info_alter in core/modules/media_library/tests/modules/media_library_form_overwrite_test/media_library_form_overwrite_test.module
media_library_form_views_form_media_library_page_alter in core/modules/media_library/media_library.module
Alter the bulk form to add a more accessible label.
menu_ui_form_node_form_alter in core/modules/menu_ui/menu_ui.module
Implements hook_form_BASE_FORM_ID_alter() for \Drupal\node\NodeForm.
menu_ui_form_node_type_form_alter in core/modules/menu_ui/menu_ui.module
Implements hook_form_FORM_ID_alter() for \Drupal\node\NodeTypeForm.
node_form_system_themes_admin_form_alter in core/modules/node/node.module
Implements hook_form_FORM_ID_alter().
olivero_form_node_preview_form_select_alter in core/themes/olivero/olivero.theme
Implements hook_form_FORM_ID_alter().
olivero_form_system_theme_settings_alter in core/themes/olivero/theme-settings.php
Implements hook_form_FORM_ID_alter() for system_theme_settings.
olivero_form_views_exposed_form_alter in core/themes/olivero/olivero.theme
Implements hook_form_views_exposed_form_alter().
options_test_form_entity_test_entity_test_form_alter in core/modules/options/tests/options_test/options_test.module
Implements hook_form_FORM_ID_alter().
page_cache_form_test_form_page_cache_form_test_alter in core/modules/page_cache/tests/modules/page_cache_form_test.module
Implements hook_form_FORM_ID_alter().
page_cache_form_test_module_implements_alter in core/modules/page_cache/tests/modules/page_cache_form_test.module
Implements hook_module_implements_alter().
phpass_form_system_modules_uninstall_confirm_form_alter in core/modules/phpass/phpass.module
Implements hook_form_FORM_ID_alter() for system_modules_uninstall_confirm_form.
search_form_search_block_form_alter in core/modules/search/search.module
Implements hook_form_FORM_ID_alter() for the search_block_form form.
standard_form_install_configure_form_alter in core/profiles/standard/standard.profile
Implements hook_form_FORM_ID_alter() for install_configure_form().
syslog_form_system_logging_settings_alter in core/modules/syslog/syslog.module
Implements hook_form_FORM_ID_alter().
system_form_form_test_alter_form_alter in core/modules/system/tests/modules/form_test/form_test.module
Implements hook_form_FORM_ID_alter().
taxonomy_test_form_taxonomy_term_form_alter in core/modules/taxonomy/tests/modules/taxonomy_test/taxonomy_test.module
Implements hook_form_BASE_FORM_ID_alter() for the taxonomy term form.
test_theme_settings_form_system_theme_settings_alter in core/modules/system/tests/themes/test_theme_settings/theme-settings.php
Implements hook_form_system_theme_settings_alter().
test_theme_theme_form_system_theme_settings_alter in core/modules/system/tests/themes/test_theme_theme/test_theme_theme.theme
Implements hook_form_system_theme_settings_alter().
umami_form_search_block_form_alter in core/profiles/demo_umami/themes/umami/umami.theme
Implements hook_form_FORM_ID_alter().
user_form_system_regional_settings_alter in core/modules/user/user.module
Implements hook_form_FORM_ID_alter() for \Drupal\system\Form\RegionalForm.
user_form_test_form_user_cancel_form_alter in core/modules/user/tests/modules/user_form_test/user_form_test.module
Implements hook_form_FORM_ID_alter() for user_cancel_form().
views_form_test_form_views_form_media_media_page_list_alter in core/modules/views/tests/modules/views_form_test/views_form_test.module
Implements hook_form_BASE_FORM_ID_alter().
views_form_views_exposed_form_alter in core/modules/views/views.module
Implements hook_form_alter() for the exposed form.
views_test_checkboxes_theme_form_views_exposed_form_alter in core/modules/views/tests/themes/views_test_checkboxes_theme/views_test_checkboxes_theme.theme
Changes an exposed "type" filter from a multi-select to checkboxes.
views_test_data_form_views_form_test_form_multiple_default_alter in core/modules/views/tests/modules/views_test_data/views_test_data.module
Implements hook_form_BASE_FORM_ID_alter().
views_ui_test_field_form_views_ui_add_handler_form_alter in core/modules/views_ui/tests/modules/views_ui_test_field/views_ui_test_field.module
Implements hook_form_FORM_ID_alter() for views_ui_add_handler_form.