This is a standard youtube downloader that illegally distributes GPLv3 FFMPEG.EXE as part of a closed source proprietary licensed product, they probably think that dynamically downloading the GPLv3 parts after installation somehow makes their stealing GPLv3 licensed FFMPEG.ORG Intellectual Property legal but without allowing the installation to complete by installing the stolen code dynamically the product does not function so it is still distributing GPLv3 software illegally…
That said the restrictions on the always free unregistered version does not render the illegal product unusable… and it can be allowed to update without worrying about losing the license as the lifted limitations are of no real use as they just confirm to youtube back-end scripts you are running an unauthorised bulk downloading bot and they will challenge you to login to prove you are human and IF you do login with a valid google login that is used to access playstore etc too you risk summarily having the account banned and losing access to your purchases and emails. Any decent back-end scripting should be able to spot downloader bot software like this as they all download the entire video before downloading the audio and then merge them using FFMPEG.EXE and NEVER download the adverts on queue. The normal viewing of a youtube video downloads the audio and video files and merges them in player and request advert breaks when the script says to.
There will come a time when downloaders will have to emulate the behaviour of live viewing in a browser or mobile app and pretend to display adverts but not actually merge them into the downloaded file.
Size on disk once installed is 297MBytes, the exe provided here is a downloader for the first installer which is also a downloader for the 3rd party components some of which are legal as they are public domain to avoid litigation and others are GPLv3 which are illegal and should have been the LGPLv3 builds with attribution and license documentation… but this developer like so many others only cares about their copyrights and think nothing of abusing the copyrights of others hence the entire concept of illegally abusing the copyright of content producers and ad revenue generation to pay for the service and content producers.