Man, I´ve already made a post for it down below same forum!
I do not think it´s a laser, I suspect something like a LED matrix through a planoconcave gallium arsenide lens.
The tracker shouldn´t be something more than a beacon mechanism, they target the receivers lighting up separate segments of the matrix.
The lens should also help with tracking, get fewer sense elements for larger area.
If you can see in the video, Linus is powering up at some point 2 trains and a speaker, multiple devices.
If they were not using a LED matrix and they were using a laser, they would just lose so much power output even with good and fast galvos.
Plus solar panels tend to get quite sensitive with shadows, a laser would only create a flat spot effectively making the rest of the panel look
like a shaded area.
Regards, Lefteris