Code signing is the process of digitally signing executables and scripts to confirm the software author and guarantee that the code has not been altered or corrupted since it was signed. The process employs the use of a cryptographic hash to validate authenticity and integrity. [Wikipedia link]
Starting with Version 3 beta 2 (March 2nd, 2018) the kits are signed, the certificates are below. If you see a popup window 'Windows protected your PC' when installing then click More info and check the publisher is shown as SDR-radio.com Ltd.