everyone in the org can read them. One can also subscribe to other org's mailing lists.
I'm a software guy who for 1.5 years worked for a hardware company with a relatively strict upwards-only information reporting structure. It wasn't even for secrecy, it's just that the people running it didn't understand the concept of collaboration at all. They were a mix of physicists and economists. Really smart but also, as it turned out, very 'square' people. It was a relatively small company, around 100 people.
It felt quite soul-crushing after a busy week to have to spend mental efforts writing up a report to someone 1-3 levels up... especially if you had no idea if it was ever read. And then do this every single week. If colleagues could read and learn from this effort it would make a lot more sense.
Never again. Went back to the relatively speaking much saner software world after that experience.
There are ways to test that.
You could just not submit the report, and see if anybody complains.
Or prepare the report, but intentionally corrupt the file before submitting it, and see if anybody complains.
Or prepare the report, and in it ask if anyone is actually reading it, and ask that they contact you if they are.
I admit I never had the guts to submit a slide which asked if anyone was reading it. It did cross my mind.
(It was a Microsoft-by-default-company, as many small hardware/research-oriented companies often are, I guess.
There was also that one week epic fight needed to get approval to run MacOS/Linux in the new "software department".)