You can, for example, use a `data-testid` attribute if the element can't be identified reliably with another attribute, such as the `id` or `role`.
You can, for example, use a `data-testid` attribute if the element can't be identified reliably with another attribute, such as the `id` or `role`.
As I said in my (earlier) response to you: using the "class" attribute for semantic, non-styling purpose is not "overloading" or misusing it. It is simply using it. (Just like the folks who developed CSS were able to get use out of element classes by baking tier-one support for them into their selector language. CSS has no claim to the right and proper use of an attribute that predates CSS.) To argue against this is revisionism.
The HTML5 data attributes also aren't a replacement for proper use of the class attribute, either. What the class attribute encodes (surprise) the class that the content belongs to. The data attribute payload encodes a particular value associated with a given key for a particular instance (e.g. the testid payload from your own example). And aside from the use cases being incomparable, the HTML spec says they shouldn't be used the way you're saying.