Retrieves the translation of $text in a gettext context, and escapes it for safe use in an attribute. If there is no translation or the domain isn't loaded, the escaped original text is returned.
<?php $translated_text = esc_attr_x( $text, $context, $domain ) ?>
esc_attr_x() is located in wp-includes/l10n.php
.
L10n: translate(), __(), _e(), _n(), _x(), _ex(), _nx(), esc_attr__(), esc_attr_e(), esc_attr_x(), esc_html__(), esc_html_e(), esc_html_x(), _n_noop(), _nx_noop(), translate_nooped_plural()