The universal format for PCB layout is the Gerber file also known as RS-274X which started as a proprietary format by the Gerber company and becoming a standard over the years. It is a vector type of spec, but not much like an SVG file. It derives from the day when PCBs masks were made optically using a machine with a light source with various apertures (shapes) and would move the film in the X/Y direction. So the file contains commands to set the aperture, open the shutter, move the film and close the aperture. The command set closely matches these operations. Now the machines are essentially laser printers but the file format has not changed much.
There is a way to do step and repeat of the commands, but I think it is intended for duplicating the entire PCB multiple times on a panel, not for repeating a portion of the layout a few times.
Here is a link for the RS-274X format...
After getting a feel for the language of the document, look at the section 4.13 on the Step and Repeat command.