Note: this will only works once/if IE11 is not supported.
This can be replaced with a much simpler clip-path, however clip-path is not supported on IE11 and non-Blink Edge browsers (non modern supported in browser support matrix).
Please QA on IE11 and modern Chrome + modern Firefox. https://en.wikipedia.beta.wmflabs.org/wiki/Sample_page
When JS is disabled a browser-based tooltip should display on hover.
When page previews is disabled a browser-based tooltip should display on hover.
the browser-based tooltip should not display on hover when page previews is enabled