Thanks! I also found some confirmation that `::-webkit-scrollbar { display: none }` is indeed a useful thing to support -- just a few weeks ago, we ran into bug 2016775 where Slack used that exact formulation to hide the "real" scrollbars (so that Slack can draw its own synthetic scrollbar).
Bug 1977511 Comment 21 Edit History
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Thanks! I also found some confirmation that `::-webkit-scrollbar { display: none }` is indeed a useful thing to support -- just a few weeks ago, we ran into bug 2016775 where Slack used that exact formulation to hide the "real" scrollbars (so that Slack can draw its own synthetic scrollbar). And because we don't support that syntax, Firefox showed two superimposed scrollbars: the real one and slack's synthetic one.