How accessible is this approach to screen reader users and people who rely on keyboard interaction alone? Edit: A quick test reveals these tooltips are not accessible at all.
`aria-label` is essentially used twice here - both to populate the tooltip's contents, and to provide an accessibility label to the element that can be read off by a screen-reader.
I proposed these changes to the maintainers under an existing a11y issue (yay to people thinking about it!), but pointed out that if folks are using this library to supplement the contents of an element with a tooltip instead of labeling it, then the a11y changes are not ideal because a screen-reader will omit the element's contents in favor of whatever is inside the tooltip. My gut tells me that this library is mainly used to annotate things like icons.