Screen2Shot

Support

Nothing happens when I press ⇧⌘9.
Open the Screen2Shot menu in the menu bar. If it says the shortcut is taken by another app, that app owns ⇧⌘9 — change its shortcut, or use Capture Area from the menu.
macOS asks for Screen Recording access.
Screen2Shot needs it to see what is on your screen at the moment you press the shortcut. Turn it on in System Settings → Privacy & Security → Screen & System Audio Recording, then quit and reopen Screen2Shot.
Where are my screenshots saved?
Copy puts the image on the clipboard. Save asks where to put the PNG and remembers the folder you chose; the first time it opens in Pictures.
How do I stop it starting at login?
Open the Screen2Shot menu and untick Start at Login, or remove it in System Settings → General → Login Items.
How do I quit it?
Screen2Shot menu → Quit Screen2Shot.

Contact

Write to contact@sshlg.me. Include your macOS version and what you pressed.