date_combo_element_process in core/modules/date/date.elements.inc

Process an individual date element.

date_combo_validate in core/modules/date/date.elements.inc

Validate and update a combo element.

file_field_widget_process in core/modules/file/file.field.inc

Render API callback: Processes a file_generic field element.

image_field_widget_process in core/modules/image/image.field.inc

An element #process callback for the image_image field type.

link_field_process in core/modules/link/link.module

Processes the link type element before displaying the field.

taxonomy_autocomplete_validate in core/modules/taxonomy/taxonomy.module

Form element validate handler for taxonomy term autocomplete element.