Files v0.1.14

• One Files at a time (Settings → General → Windows, on by default): opening a folder or starting Files again uses the running one, which opens the folder in a new tab and comes to the front. The second start talks to it over 127.0.0.1 with a random token only your user can read.
• Windows: Settings → Default apps can make Files open folders and drives instead of Explorer (double-click on the desktop and in Explorer, downloads, other apps), through your user's registry without administrator rights. "This PC", Control Panel and other shell folders go back to Explorer; Restore Explorer and uninstalling Files undo it.

Installing: the builds are not signed by Apple or Microsoft yet.
macOS: open it once, then System Settings → Privacy & Security → Open Anyway.
Windows: SmartScreen → More info → Run anyway.
Linux: chmod +x the AppImage.