Just noticed a couple of interesting messages on my laptop, now that I am on holiday:
wlo2: Limiting TX power to 30 (30 - 0) dBm as advertised by ...:43
wlo2: Limiting TX power to 20 (20 - 0) dBm as advertised by ...:7c
I assume this is the AP / router telling my laptop to whisper instead of shouting from the rooftops, right?
In that case, is it something I could also apply at home on OpenWRT? My flat is fairly compact and it would make sense to have such a setting.
The clients are just accepting the IEEE 802.11d regdom hints emitted by the router. These are fixed regulatory limits, mandated by your country's laws and not dynamic or per-client limits.
So I should be seeing the same messages when connected to my own AP?
I do have "option country IT" in /etc/config/wireless so I'll check back once I am home and followup here.
You might not necessarily see a message if the laptop is already configured to the same country as your router as there would be no change required to the limit.
In theory I am still in the same country, barely 
EDIT: what I find most interesting is that one AP is asking for max 20 and the other for max 30, within the same network.
Well, at home I get no such messages. Both the laptop and the router have REGDOMAIN=IT.
I can imagine that the other AP was configured for lower limits than in the "IT" domain, then.