Replico isn't notarized by Apple yet, so macOS shows a one-time security prompt on first launch. Here's how to get past it, takes about 10 seconds.
Download the .dmg below, then double-click it once it's finished downloading.
Drag the Replico icon onto the Applications shortcut in the window that opens, then eject the disk image.
Double-click Replico from your Applications folder. macOS will block it with a dialog that only offers "Done" or "Move to Trash". This is expected. Click Done (don't trash it).
Open System Settings → Privacy & Security, scroll down to the Security section. You'll see "Replico was blocked to protect your Mac." Click Open Anyway, then confirm with your password or Touch ID.
Launch Replico again from Applications or Spotlight. A final confirmation dialog appears with an Open button. Click it, and Replico launches normally from then on, every time.
xattr -cr /Applications/Replico.app once after installing. This clears the quarantine flag so Replico opens immediately, no prompts.