The coordinate marker gets rendered by WebOffice 10 R3.
Coordinate marker is implemented using a "logo image" function field with the technical ID "syn_coord_marker". As soon as such a field is configured the coordinate marker display on the print gets activated (grid together with geo-referenced coordinate markers in place of the logo image).
Note: For metric coordinate systems with long coordinate values it is recommended to use a size of 1,8 cm x 2,4 cm for the "logo image" function field.
'Insert logo' function in WebOffice plotten author toolbar

Technical ID "syn_coord_marker" and size of logo image function field
The logo image will be displayed with a geo-referenced coordinate marker in its position on the print. Depending on the height-width ratio of the logo image, the reference markers are aligned horizontally or vertically. In case the width is larger than the height the reference markers will get displayed horizontally.

Geo-referenced horizontal coordinate marker with X/Y coordinates

Geo-referenced vertical coordinate marker with X/Y coordinates
More coordinate markers are displayed directly on the print in a 10x10 grid.

Grid with reference and further coordinate markers on the print