0) Google and wikipedia *can* be your friends
1) It's an "Amiga clone" made on FPGA (basically programmable chips, which means if you program one to "act" like an Amiga, and another to "act" like an Atari (heresy?!), they'll look like the same chip externally, but internally they will be "wired" differently, the first being the superior choice, of course :-D ).
2) RoHS refers to basically environmentally (and human) friendly electronic components. Usually many of the chemicals and materials used in electronics can be poisonous to humans and other lifeforms. RohS compliant components are supposed to have reduced amounts of such harmful substances. As the RoHS mandates are not in effect in various countries that produce electronics, this makes many of the older components unavailable or not reproducable. In general: it makes the stuff needed for the flicker fixers harder to find and/or make.
3) That's up to the designers to decide. Ask'em! But basically they haven't recouped their money/time investment so they won't give up their IP (intellectual property, in this case the schematics) 'til they deem appropriate.
