Alter the results of taxonomy_term_view().
This hook is called after the content has been assembled in a structured array and may be used for doing processing which requires that the complete taxonomy term content structure has been built.
If the module wishes to act on the rendered HTML of the term rather than the structured content array, it may use this hook to add a #post_render callback. Alternatively, it could also implement hook_preprocess_HOOK() for taxonomy-term.tpl.php. See drupal_render() and theme() documentation respectively for details.
$build: A renderable array representing the taxonomy term content.
Drupal\taxonomy\Term $term: The taxonomy term being rendered.
function hook_taxonomy_term_view_alter(&$build, Drupal\taxonomy\Term $term) {
if ($build['#view_mode'] == 'full' && isset($build['an_additional_field'])) {
// Change its weight.
$build['an_additional_field']['#weight'] = -10;
}
// Add a #post_render callback to act on the rendered HTML of the term.
$build['#post_render'][] = 'my_module_taxonomy_term_post_render';
}