This dish is the trademark of Solo, Central Java, even more than 'timlo' (see another page of this section).
The name 'sego liwet' or 'nasi liwet' means more or less 'boiled rice'.
It refers to the way the rice is done just for this dish; usually we boil some rice in a pot ('manci' in Javanese, 'panci' in Indonesian), and stir it until the bubbles come out, at which point we take the rice out and put it into the steamer, named 'dandang' in Javanese (there is no Indonesian name for it). Both kitchen props are made of alluminium.
That was before the advent of electric rice-cookers.
And this advent is householdwise -- until today, a lot of Javanese homemakers still cook rice that way, since electric rice-cookers, though might be affordable to many (as long as it is made in China, it won't cost more than US$ 15), suck too much electricity and in the end cause a jump of monthly bill.
Anyway, the Solonese 'nasi liwet' is dubbed so because the rice is to get cooked in the pot without ever getting transfered into a steamer. So it is considerably softer than the usual.
Of course we don't eat just rice; the Solonese have fixed what to be eaten with this kind of rice a few hundred years ago: fried 'jepan' with chili and coconut milk, which we call 'sambel goreng jepan' and in Indonesian it is called 'sambal goreng labu siam' (see the veggies section).
Then some thick coconut milk with a little salt, which is cooked until it got bubbles, called 'arèh', is put on the rice. Eggs and chicken boiled in coconut milk are also added. Then a little chili sauce, handmade, is to make the dish complete, plus a large shrimp cracker ('krupuk urang' in Javanese, 'kerupuk udang' in Indonesian).
Nasi liwet is that simple; so it is really beyond comprehension why the Solonese chose it as their character-representing dish, or why other people come to attach it to them.