josm:tldr:61fd6
This command is a reference to the Java OpenStreetMap Editor (JOSM) command-line interface.
The command starts with "josm" which is the executable command used to launch the JOSM editor. Following that is the "--download" flag which tells JOSM to download data from the OpenStreetMap server.
The parameter within curly braces "${minlat,minlon,maxlat,maxlon}" provides the coordinates of a bounding box. The "minlat", "minlon", "maxlat", and "maxlon" represent the minimum and maximum latitude and longitude values that define the rectangular area of the map data to be downloaded.
By specifying the bounding box, JOSM will retrieve map data from the OpenStreetMap server for that particular area, which can then be edited or viewed within the JOSM editor.