This is a "ping bar" for MacOS toolbar.
By default it shows 3 pings: to 126.96.36.199, 188.8.131.52, and the local router.
When ping is not going through, the toolbar widget background highlights red.
On click it will show ping graphs.
If you don't want it working in background, tick "Do NOT keep content active in background".
Link: Ping Bar download/install from share.folivora.ai
You can adjust the maximum time depth and ping destinations in the widget's source: