If you're unaware of the recent history of this project, the big Fallout 4 update that came out a few months ago broke this project. GOG worked with them to build an installer that would downgrade Fallout 4 to the required version to run this (hence the GOG logo at the start). Good guy GOG to the rescue.
Any reason to think this would be a probable takedown? Mods on Bethesda games have historically been a thriving community unless they directly infringe on another company's copyright.