The libmanette gamepad backend does not report the button 16 (BTN_MODE, e.g. the Playstation button in DualShock 3/4/5). Chromium and Firefox report that correctly.
Pull request: https://github.com/WebKit/WebKit/pull/23771
Committed 274022@main (37a85d6c3252): <https://commits.webkit.org/274022@main> Reviewed commits have been landed. Closing PR #23771 and removing active labels.