The Brooks Campagnolo edition saddle that used narrow rails and special seat post rail clamps had a longer fore/aft adjustment length.
I don't know who brought those two mfgs together, Bianchi? Legnano?

There was an evolution in thinking of saddle position before the framebuilders caught up. Before steeper seat tube angles there were 7 seat posts which had a horizontal tube allowing the saddle to be moved forward.

the UCI has a say in this too- at least for international level racing bikes.
it has diverged from one number but for road bikes the forward point of the saddle is to be at least 50 mm behind the bottom bracket. In review there may have been a clarification about the useful seating part of the saddle positioned to that dimension via appeal.

this type forming was to prevent recumbents and later "tri bikes" from polluting the peloton.

for a long period seatposts or posts and clamps placed the attachment point of a saddle behind the seat post. - or no more forward of the centerline- now called a setback seatpost.