In detail: It's a default message. Windows checks for a trusted SPC in an app, it's a form of certificate that you rent. 400$ a year for a Microsoft owned one, some are cheaper but aren't always classified as "trusted" by Microsoft. It basicly says that we are real persons.
Win doesn't check for any form of maleware in this progress, it only looks for a valid SPC. If that file is missing, yout get that message.
If you want to be sure if an app is save, alway run an antivirus app or similar stuff to check it.