Double Curly Brackets in Php

In your example {{image-about}} tells WordPress to use the image defined in ['attachments']['image-about'] as the thumbnail for those posts in the ‘starter content’. This functionality is specific to the “Starter Content” feature added in WordPress 4.7, which is described here, and not a PHP language feature.

Hata!: SQLSTATE[HY000] [1045] Access denied for user 'divattrend_liink'@'localhost' (using password: YES)