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

big_pipe_page_attachments in core/modules/big_pipe/big_pipe.module
Implements hook_page_attachments().
book_test_page_attachments in core/modules/book/tests/modules/book_test/book_test.module
Implements hook_page_attachments().
common_test_page_attachments in core/modules/system/tests/modules/common_test/common_test.module
Implements hook_page_attachments().
content_translation_page_attachments in core/modules/content_translation/content_translation.module
Implements hook_page_attachments().
contextual_page_attachments in core/modules/contextual/contextual.module
Implements hook_page_attachments().
css_disable_transitions_test_page_attachments in core/modules/system/tests/modules/css_disable_transitions_test/css_disable_transitions_test.module
Implements hook_page_attachments().
js_testing_ajax_request_test_page_attachments in core/modules/system/tests/modules/js_testing_ajax_request_test/js_testing_ajax_request_test.module
Implements hook_page_attachments().
js_testing_log_test_page_attachments in core/modules/system/tests/modules/js_testing_log_test/js_testing_log_test.module
Implements hook_page_attachments().
off_canvas_test_page_attachments in core/modules/system/tests/modules/off_canvas_test/off_canvas_test.module
Implements hook_page_attachments().
settings_tray_test_css_page_attachments in core/modules/settings_tray/tests/modules/settings_tray_test_css/settings_tray_test_css.module
Implements hook_page_attachments().
system_test_page_attachments in core/modules/system/tests/modules/system_test/system_test.module
Implements hook_page_attachments().