Seat Tube lug with holes in cross shape: is it unique? for what purpose?

[Fifthgrace]

I have a Sedazzari and a contact with what he thinks is a Sedazzari frame. Both have 4 drill holes in cross-shape in the seat tube lug. Is this a distinctive feature of Italian 70s/80s frames or is it specific to a limited number of frame makers? Is it due to the way the lug is made or does it help enable frame construction, or is it to reduce weight?

 

[dyna-ti]

I thought this type of thing was to vent brazing/welding gases or condensation

 

[Nob]

As above

 

[keithglos]

Those holes are in the seat tube not the lug.
Some frames just had a chiselled hole, some manage without gas holes.
Keith