If you run SHOW ENGINES on a version of MariaDB with the Performance Schema enabled, you'll see the following storage engine listed.

SHOW ENGINES;
+--------------------+---------+----------------------------------+--------------+------+------------+
| Engine             | Support | Comment                          | Transactions | XA   | Savepoints |
+--------------------+---------+----------------------------------+--------------+------+------------+
| ...                |         |                                  |              |      |            |
| PERFORMANCE_SCHEMA | YES     | Performance Schema               | NO           | NO   | NO         |
| ...                |         |                                  |              |      |            |
+--------------------+---------+----------------------------------+--------------+------+------------+

This row will also appear if the PERFORMANCE_SCHEMA is supported but disabled, because the database and its tables will exist (but they will be empty).

The SHOW ENGINE PERFORMANCE_SCHEMA STATUS statement is also available, which shows how much memory is used by the tables and internal buffers.

However, the PERFORMANCE_SCHEMA is not a regular storage engine for storing data, it's a mechanism for implementing the Performance Schema feature.