Both the multi-edit select widget and the associated checkboxes are currently completely un-labeled and are next to impossible to handle through AT.

The select widget should have either a label (possibly hidden through the relevant CSS class) or aria-label. The checkboxes should have either an aria-label or a aria-labelledby attribute to identify (name) them.

With Firefox: Right-click / control-click on element, choose “Inspect Accessibility Properties” from the context menu. The accessibility inspector displays an angry red warning about the need for the element to be labeled.

Attached: screenshot from the Article pane with Firefox 107b Accessibility inspector