Unfamiliar Network Listed

As Keith Barkley has noted, the item "Network" would indicate that your Mac has found a device on your local network that has sharing enabled. For example, this could be a Time Capsule, or another computer/server.

If you click on Network, what device(s) show up?

Just someone that has sharing turned on.

What is the name? That might give us a clue as to what device it is.

Again, any device that shows up under Locations > Network, have been configured to potentially share files. I already gave you two examples of what these devices could be. Do you administer this network? If so, then you would know what these devices are.

I have lots of these on my "network" at work.

There are PCs, Servers, other Macs...

They are on the same IP subnet but are not able to read/write data between them unless I request connection/permission:

No, it means someone is letting you share their files.

Without knowing anything about your network, it will be difficult to assist you. Is this a home, small business, or company network? Do you have any PCs or IoT devices, Smart TVs, etc. connected to it? The more details you can provide us, the better we can help you ... albeit this is not directly an Apple-product issue.