I'll admit when I first saw this, I was put off by the idea of having a separate tool to do something that _should_ be baked into the filesystem. But honestly,

I'll admit when I first saw this, I was put off by the idea of having a separate tool to do something that _should_ be baked into the filesystem. But honestly, this a pretty close to a very Unixy way of solving the problem. Have a separate (and importantly: optional) tool that does the job and does it well. Additionally, Linux _does_ support tagging files right in the filesystem via the user.xdg.tags xattr. Although it looks like Dolphin is one of the few userspace tools that knows about it.