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.
Plus, they needed a place to host that big a mod with connections to Bethesda to prevent a probable takedown order…
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.
It was mentioned in one of their previous interviews as reason to parner with gog. I’ve unfortunately not bookmarked it, though, and I’m too lazy to search for it, sry.
edit: found it: “At the very least, GOG is sure that its support for Fallout: London won’t upset Bethesda,“They’re also our partners so we wouldn’t want to do anything to harm our relationship.””
in https://www.thegamer.com/fallout-london-gog-release-delay-fallout-4-update-interview/