The usage of the Mapillary Expert Filter is largely the same as for the JOSM Filter dialog.

The major difference is that all Mapillary Point Object layers (including traffic sign layers) are filtered by this dialog.

In order to get examples of what tags look like for Mapillary Point Objects, follow these steps:

1. Ensure that your current layer is an OpenStreetMap data layer
2. Download an object detection layer (Imagery -> Mapillary traffic signs layer or Mapillary point features layer)
3. Click on one of the point features
4. Switch to the object detection layer
5. Look at the JOSM Tags/Memberships panel