field_ui_field_edit_form in core/modules/field_ui/
Form constructor for the field instance settings form.
file_settings_form in core/modules/file/
Form callback for file settings.
link_field_instance_settings_form in core/modules/link/link.module
Implements hook_field_instance_settings_form().
path_patterns_form in core/modules/path/
Form builder; Configure the URL alias patterns.
system_site_maintenance_mode in core/modules/system/
Form builder; Configure the site's maintenance status.
user_settings_email in core/modules/user/
Form builder; Configure user email settings for this site.