Marshall has copyright on his lyrics, you just said yourself patents and copyright are different things.

Sufficiently different rip-offs that don’t confuse consumers as being the original should be legal. They already are as far as copyright is concerned.

Many design patents should never have been registered, and should lose when defended in court. Design trademarks are a third similar issue.

It doesn’t actually matter too much. They use mostly our data, so legally I think it’s ODBL too, and we can import anything genuinely useful they do.

Overture is a separate project so they can add stuff OSM doesn’t want like data generated from imagery that is not checked by people. That might make Overture better in areas where osm data is sparse. They can also restrict other things only import tags they like, or merge some tags that mean similar things to make it easier for data consumers.

It’s going to have some metadata to that effect yes, like a file index or number of parts or total extracted file size. I don’t know the details, I’ve used them I haven’t read the spec. rar is Rarlab’s proprietary format so there might not even be a public spec.
They’re normally all the same size except for the last part, so it’s not that file 1 is just an index.

Yes, it asks for the next part if it’s not in the same folder with the same name, doesn’t really make a difference what it’s stored on. Multipart zip and tar also exist.

Multipart archives still exist. They’re now used for file sharing websites that have a maximum file size. Before that they were for unreliable p2p networks, so you didn’t lose the parts you’d already downloaded when your peer goes offline. Originally it was to fit something big on multiple cd-roms or floppies.

Opening somthing.rar also reads the data in somthing.r01 through somthing.r15 etc