But it seems to be on some sort of public server these days, so some pages become inaccessible with bandwidth.
The screw mount is 57x1mm and the flange to film distance is 101.7mm, but it is possible for lenses to protrude into the mirror box, thanks to the falling mirror design on the S-series and split mirror on the EC-series. Bronica used to sell screw caps that could be drilled like lensboards so press photographers could adapt their press lenses easily to the system. Today you would just have a simple threaded ring made.
I have the Type 2 bellows, and I also have a Bronica-Canon FD (bayonet to bayonet) adapter, so I can use my Tamron SP 90 Macro and my FD 35/2.8 Macrophoto (and with that adapter, I have a Luminar I can use) on the Bronica. At macro distances they cover. I also have a LTM-FD adapter, so that lets me use enlarging lenses, and I can reverse mount them with a reverse adapter that mounts to the Bronica bayonet. It's a very handy thing.