vents in door jambs

[Blazer_Lover]

In the course of gathering parts for my project, I've noticed that some doors have vents in the door jambs and some have solid filler panels. I've read that the these openings in the door jambs allow the removal/installation of the door latch. But why do some doors have vents and some have solid panels? Thanks

 

[SunlitComet]

vented ones maybe for those without a/c? or down the years change because of complaints?