What is in Yii/php?

Question

Yii

<?= ... ?>
guys, the question, of course, may seem silly, but I read the Yii2 off-docs and this moment is not described / did not find there ...
something related to the template engine, somehow it processes it ... in general, a
space, do not kick, give an answer

Answer 1

This is PHP syntax.
Output the required variable; abbreviated notation.
Equivalently<?php echo ... ?>

Answer 2

PHP code MUST use the full <?php ?> tags or the short form <?= ?>. Use of other variants of tags is NOT ALLOWED.
www.php-fig.org/psr/psr-1/ru/#2-1-%D0%A2%D0%B5%D0%...