This was first reported in the HAN accessibility report.
The CKeditor resource picker has a dropdown button that does not have any text alternative
https://github.com/xwiki/xwiki-platform/blob/6bbb277528374f801a3c256fd281234db844d9bb/xwiki-platform-core/xwiki-platform-ckeditor/xwiki-platform-ckeditor-plugins/src/main/webjar/xwiki-resource/resourcePicker.js#L35
