为什么表CHARSET设置为utf8mb4，COLLATION设置为utf8mb4_unicode_520_ci

I've recently noticed that, when ever I start a new WordPress project, my tables' collation automatically changes from utf8_unicode_ci (which I select when I create a new DB from PhpMyAdmin) to utf8mb4_unicode_520_ci.I've recently noticed that, when ever I start a