If you have never seen these before, I can certainly understand your confusion. Please rest assured that this is not something which you need to address; it merely provides insights into the logs of which specific pages have thrown 403 (access denied, e.g. if you attempt to access something without being logged in) and 404 (page not found, e.g. if you attempt to access something which has now been removed, never existed, or merely moved elsewhere) HTTP errors.
If you suddenly notice a particular page receiving a large amount of 403s or 404s, it might be worth investigating why users are attempting to access this page. One instance could be that an incorrect link has been shared in a newsletter, or maybe content which used to be on path A has been moved to path B without the main link being updated.
As of right now though, you can safely leave both reports as is, no worries!