Skip-to-content link doesn't lead anywhere
A skip link is a hidden link, usually the first focusable element on a page, that lets keyboard users jump straight past the navigation menu to the main content. This check found a skip link present on this site, but its target, the place it's meant to jump to, doesn't exist on the page or isn't focusable. A keyboard user who activates the skip link expecting to land on the main content instead has their focus go nowhere, which is arguably worse than not having a skip link at all, since it looks like the site is broken rather than simply missing a feature. Your developer should make sure the skip link's target, for example href="#main-content", matches an id on a focusable element, such as a main element with id="main-content" and tabindex="-1". Test it by pressing Tab then Enter and confirming focus lands on the main content. Budget about fifteen minutes.
Why this matters
A keyboard user who activates the skip link expecting to land on the main content instead has their focus go nowhere, which is arguably worse than not having a skip link at all, since it looks like the site is broken rather than simply missing a feature.
How to fix it
Your developer should make sure the skip link's target, for example href="#main-content", matches an id on a focusable element, such as a main element with id="main-content" and tabindex="-1". Test it by pressing Tab then Enter and confirming focus lands on the main content. Budget about fifteen minutes.