[feature request] Custom first boot animation
There are many offerings for hardware that come preinstalled with Linux these days, often with their own vendor-specific additions. The Dell XPS 13 Developer laptop line is one such device, and for several years it came with its own custom first boot animation.
For comparison, an early version of Mac OS X had a first boot animation which would seamlessly transition into an initial setup.
Adding the option to play a video file as the Plymouth splash screen transitions into the initial setup session could be an straightforward way for distributions and hardware vendors to differentiate themselves and have their own branding without having to maintain extensive patches, similar to how they have their own custom logos and backgrounds today.
I believe that such a feature would have to be configurable enough to adapt to different device form factors, such as having separate video files for landscape orientation and portrait orientation. An audio file may also have to be specified to ensure that only one audio stream is playing in the event that a multi-monitor setup is detected.