“SynfigStudio” cannot be opened because the developer cannot be verified.
What to do with this? Shouldn’t you get it verified for mac?
Hi and Welcome here 
This is not a Synfig issue, it is MacOS “defense”.
See here to solve this issue: Safely open apps on your Mac - Apple Support
If you want to open an app that hasn’t been notarized or is from an unidentified developer
Running software that hasn’t been signed and notarized may expose your computer and personal information to malware that can harm your Mac or compromise your privacy. If you’re certain that an app you want to install is from a trustworthy source and hasn’t been tampered with, you can temporarily override your Mac security settings to open it.
If you still want to open an app for which the developer cannot be verified, open System Preferences.*
Go to Security & Privacy. Click the Open Anyway button in the General pane to confirm your intent to open or install the app.
The warning prompt reappears, and if you’re absolutely sure you want to open the app anyway, you can click Open.
The app is now saved as an exception to your security settings, and you can open it in the future by double-clicking it, just as you can any authorized app.
1 Like
proprietary software strikes again !
We have to be part of Apple’s Developer Program for $99 per year.
Also, obey their guidelines App Review - App Store - Apple Developer (yes, it’d be great for MacOS users), but we have so few developers with MacOS…