I can reproduce this bug here on meta on unsupported-install, there’s a link to /tag_groups that returns a 404.
That said, I did hide this button for non-staff users in my community just to avoid the clutter:
body:not(.staff) #show-tag-info {
display: none;
}
You don’t need to
I do this kind of tweak as a theme component, use the ➕Install button below the list of theme components and Create new, customize the CSS and add it to the themes you want.