MacBook Air: 'Power Source: Network Adapter' battery impact?

Hey guys! I recently bought a Mac and I have a question about the "Power Source: Network Adapter" mode on my Mac. Does this mean the Mac uses power from the wall outlet? Does it bypass the battery, essentially extending battery life? Is it safe to keep it this way? It's not very often, of course. Just in case you're wondering, I have a MacBook Air with an M4.