@tf2, @JonathanBuchh, and @GLight are correct – I did some experimentation and confirmed it. Thanks, folks!
And @GLight has already answered the next question I was going to ask: What if I have two documents, in different folders, with the same name? I did an experiment there too; Obsidian automatically changes the target URL to include the folder name.
This is important to me because, for now at least, I’m using Obsidian as part of the larger system, including DevonThink and the Finder, with a lot of folders. My Obsidian usage is not self-contained and I’m still making heavy use of folders.