Gerber stayed the PCB standard with a free spec and backward-compatible versions

Every printed circuit board has to travel from the design tool to the fabrication shop, and for decades that handoff has run on one format: Gerber. Ucamco, the format's current owner, calls it the de facto standard and "the backbone of the electronics fabrication industry": all PCB design systems output Gerber and all fabrication software can handle it. In 2013 its general manager estimated over 90% of PCBs were manufactured based on Gerber.

Two design choices kept it dominant. First, the specification is free — downloadable from Ucamco, clear enough that KiCad and other open-source tools implement it directly. Second, evolution is strictly backward-compatible: the extended RS-274X version superseded the obsolete RS-274D, and when X2 added metadata about what each image means, it was designed so software that fully implements X1 can just ignore the additions. New capability never breaks the old ecosystem.

The format itself is deliberately simple: 7-bit ASCII, compact, human-readable and easy to debug. Rather than forcing the industry onto a new imaging model, Ucamco extended the format it already had — complementing Gerber with a job file for stack-up and fabrication data instead of starting over.