Some possible sensitive files were exposed, which allows an attacker to view and even download those files.
An attacker could access this file and use the information in order to perform reconnaissance actions against the website infrastructure and or sensitive data the website might hold.
To prevent this vulnerability from occurring, make sure to restrict access to these files from users without permission or remove it completely from the website
wp-content is used to store assets of a website like images, plugins, etc.
By revealing this info (Information disclosure) you will make an attacker’s job easy to see which version of plugins, themes, etc are installed and hence can find attack vectors easily.