These can be trusted by your mac (or not), but before they run the first time: you'll have to confirm you want to run them Applications downloaded from the Internet at large and signed by a known Apple Developer:.App store downloads: these are signed and are trusted by your mac.
There are 3 levels of trust your mac has into applications:
Little known tools and so: those are easier to trust form the App store indeed. Click to expand.App store for sure is fine, but you'll find more outside of it.
