wp-admin/includes/template.php:555Outputs 'undo move to Trash' text for comments.
function wp_comment_trashnotice() { ?><div class="hidden" id="trash-undo-holder"> <div class="trash-undo-inside"> <?php /* translators: %s: Comment author, filled by Ajax. */ printf( __( 'Comment by %s moved to the Trash.' ), '<strong></strong>' ); ?> <span class="undo untrash"><a href="#"><?php _e( 'Undo' ); ?></a></span> </div></div><div class="hidden" id="spam-undo-holder"> <div class="spam-undo-inside"> <?php /* translators: %s: Comment author, filled by Ajax. */ printf( __( 'Comment by %s marked as spam.' ), '<strong></strong>' ); ?> <span class="undo unspam"><a href="#"><?php _e( 'Undo' ); ?></a></span> </div></div> <?php}Introduced in 2.9.0. Unchanged from 6.7.7 through 7.1.0.
Signature, return type and hooks compared across 5 parsed releases.
src/wp-admin/includes/template.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.