This looks like it should take care of the a11y issue raised in the ticket, but does the horizontal scroll behavior work fine without this new osfHorizontalScrollKeyboard directive, and just with the tabindex="0" on that wrapper div? I would prefer to use the default browser behavior for horizontal scrolling. I worry that making our own keyboard scroll directive is going to be something that we forget to add for other elements and may create an inconsistent experience for keyboard users.

Also, according to WebAIM, it seems the keybinding for scroll behavior are the arrow-keys, and space / shift+space. Binding Home and End may be a bit unexpected for keyboard users? https://webaim.org/techniques/keyboard/#testing -- "Scroll" section on this page