I have a situation where a TH element has both scope="col" and tabindex="0" attributes, which is causing Tabbable to break with "Cannot read properties of undefined (reading 'forEach').

index.js:425 Uncaught TypeError: Cannot read properties of undefined (reading 'forEach')
at e (index.js:425:14)
at index.js:429:32
at Array.forEach ()
at e (index.js:425:14)
at e.tabbable (index.js:473:10)

Tabbable appears to be evaluating !! item.scope as true because the attribute is present, and assumes there is a ShadowRoot to process.