One other thing crossed my mind. Back in Ye Olde Days (1970's) , I designed a few boards which required edge connectors. Hard gold plating on the fingers was a standard requirement to ensure longevity of the fingers through multiple insertions/removals of the card.
I was doing the card designs at 2X size using a mylar sheet with a translucent grid sheet under the mylar for placements, both stacked/taped onto a light table, and I used an Xacto knife and a variety of "stickies" sold by Bishop Graphics.
I now distinctly recall a Bishop "sticky" for edge connectors that had a "plating bar". It added a small trace that extended from the tip of each edge finger out to a trace that ran at a right angle along the width of all the fingers. The PCB fab shop required (?) that in order to do hard gold plating of the fingers. After plating, the PCB shop cut/milled off the excess with the plating bar.
I have no idea what fabrication requirements are in this century. A brief websearch found this: