@Droidz hello again. All the time I wanted to ask. If I’m not mistaken, the pathfinder is already on the server and "local" (non-server pathfinder from the downloaded meshes) is not provided, so why this option? If it is 'false' then how will pathfinder work? It will generate paths "on the fly" without using the server?

There is old mesh and new mesh which the pathfinder uses. That pretty much is true for you to use new mesh 

Just since the last wrobot update in which this option was added (to the settings menu, I know that it existed before that, but) the pathfinder began to run into the wall, in dalaran for example. I rolled back to version 2.5.1 (19181), and it works fine.

It will simply create a straight "path" without meshes if you disable that option.

Ok got it. Old meshes are downloaded meshes, did I understand correctly? Are they still available for download?