Krita

This is what's known as a false positive: https://portableapps.com/support#false_positive

As VirusTotal reports, your antivirus currently has this issue. Note that all other antivirus engines correctly report the app as clean: https://www.virustotal.com/#/file/a5c809840b3ab3ffb5e9fa3be3383a0d2d0bfc...

You can report it to your provider and wait for them to fix their error or whitelist the app based on the VirusTotal report above. You can verify the installer you downloaded is the correct one by comparing the MD5 or SHA256 to the ones mentioned on VirusTotal. You can also check the digital signature that assures you it's the legitimate version from us.