How to easily measure signal strength of a wireless client bridge?

Is there any way to easily measure signal strength of a wireless client
bridge?

I have all the Android tools to measure signal strength of an access point.
<https://play.google.com/store/search?q=cellular-z>
<https://play.google.com/store/apps/details?id=com.vrem.wifianalyzer>
<https://play.google.com/store/apps/details?id=aws.apps.networkInfoIi>

But those free Android Wi-Fi debugging signal strength analyzers don't seem
to even _see_ the signal strength of the new wireless client bridge.

All I did to create the wireless client bridge was attach an old Linksys
WRT54Gv8.1 router (which I flashed to DD-WRT and set up as a client bridge)
to an Ethernet-only old Win10 desktop (which didn't have a Wi-Fi card).

I had copied the procedure off the net and filled in the details as I saw
them in my situation if you need the exact steps for how I set up that
wireless client bridge earlier this week.
<https://groups.google.com/g/alt.internet.wireless/c/cglQmfONISQ/m/8pzdDv5XAQAJ>

Sitting at that Win10 desktop (with the client bridge sitting on top of that
desktop) and logging into the Linksys DD-WRT interface shows the old Netgear
WNDR3400v2 home router signal is being received by the Linksys WRT56Gv8.1
client bridge at around -50dBm with the displayed "Signal Quality" graph
coming out at around 65%. 

But how can I _measure_ (easily) the signal the other way around?
How can I easily measure the signal strength of the client bridge at the
home router?

Is there an Android or Netgear or Windows tool to measure signal quality of
the Linksys client bridge on the other end (which is back at the Netgear
WNDR3400v2 home router)?

Why do they give you tools only for easily measuring one side of the bridge?

The Netgear Advanced > Administration > Attached Devices doesn't even show
the client bridge. All it shows is the IP (and what I presume is the MAC
address) of the Win10 desktop which is attached to the client bridge.

But what Android or Windows tools tell us the strength of the client bridge?