-`.mrkr`: Opens a formspec allowing you to display or delete markers.
-`.add_mrkr`: Adds markers. You can either use `.add_mrkr x,y,z Marker name` or `.add_mrkr here Marker name` to add markers. Markers are (currently) cross-server, and adding a marker with (exactly) the same name as another will overwrite the original marker.
-`.mrkr_export`: Exports your markers to an advmarkers string. Remember to not modify the text before copying it.
-`.mrkr_import`: Imports your markers from an advmarkers string (`.mrkr_import <advmarkersstring>`). Any markers with the same name will not be overwritten, and if they do not have the same co-ordinates, `_` will be appended to the imported one.