GeoHash is a JOSM plugin that displays a layer on top of the JOSM map that contains the corresponding geohashes, up to a depth of 10. This means that the geohash can have a code length of maximum 10 characters.
How to use the Geohash plug-in
The geohashes are automatically generated based on the user map view and zoom level. Increased zoom means increased depth level for geohashes. The maximum geohash code length is 10 characters.
To search for a geohash, use the Geohash plug-in dialog. Type or paste the geohash code in the text field and press the Search button. If the code is invalid, a message will be shown. Otherwise, the map view will be moved and zoomed over the selected geohash.
To clear generated geohashes, double click a geohash and all geohashes from his parent will be cleared. Also, right click on Geohash layer will show the option to ‘Clear geohashes’ that will leave only the depth one grid.