Keyboard-Accessible Pre: A Small, Dependency-Free Script for Making <pre> Elements Keyboard-Accessible
Because text in a <pre> doesn't wrap (unless you use something like white-space: pre-wrap), keyboard-users generally have no means of reading content that overflows the element (except in Firefox).
This little script uses a ResizeObserver to set and maintain the tabindex of all <pre> elements on the page, making each of them keyboard-focusable when it has overflow and not keyboard-focusable when it doesn't. When a <pre> is focusable, it also has generic role and aria-label attributes for the benefit of those using a screen-reader (role="group" and aria-label="Preformatted text that overflows visually").