The latest version of 5.8.2 is deployed. The user logged in has administrator capabilities.
It seems that “Link Categories” are hidden for installs greater than 3.5 – https://codex.wordpress.org/Links_Link_Categories_Screen

Although hidden, outputting the values of the global variable $submenu, it returns a URL i.e. wp-admin/edit-tags.php?taxonomy=link_category.

print_rgenerates the following:

[15] => Array
                (
                    [0] => Link Categories
                    [1] => manage_categories
                    [2] => edit-tags.php?taxonomy=link_category
                )

        )

When attempting to access the URI, it displays You need a higher level of permission. Sorry, you are not allowed to manage terms in this taxonomy.

• Why is the message displayed?
• Why is the URI returned when calling the global variable $submenu?
• Is it still a valid option and if yes, other what scenarios and how would it be accessible?