Partial answer: from images to codes
In Brazil (first time), the coloured regions are
Roraima (RR), Rondonia (RO), Tocantins (TO), Piaui (PI), Rio Grande do Norte (RN), Paraiba (PB), Goias (GO), Bahia (BA), Sergipe (SE), Minas Gerais (MG), Rio de Janeiro (RJ), Espírito Santo (ES), Rio Grande do Sul (RS). These are according to the official states of Brazil and the ISO standard codes.
In France, the coloured regions are
Pays de la Loire (PDL), Centre-Val de Loire (CVL), Ile-de-France (IDF), Nouvelle-Aquitaine (NAQ), Auvergne-Rhone-Alpes (ARA), Provence-Alpes-Cote d'Azur (PAC). Again these are according to the official regions of France and the ISO standard codes.
In Australia, the coloured regions are
Northern Territory (NT), South Australia (SA), New South Wales (NSW), Victoria (VIC). Again these are according to the official states/territories of Australia and the ISO standard codes.
In Turkey, the coloured regions are
Yalova (77), Nevşehir (50), Sivas (58), Artvin (8), Van (65). These are according to the ISO standard codes, this time numbers instead of letters.
In Sweden, the coloured regions are
Skåne (M/12), Blekinge (K/10), Östergötland (E/5), Örebro (T/18), Södermanland (D/4), Harjedalen, Medelpad, Angermanland, Vasterbotten, Norrbotten. This is complicated as there are different ways of dividing Sweden and the map shown in the OP here doesn't actually correspond to the counties used for ISO codes but instead to the historical provinces, which as far as I can tell don't have nice neat codes like ISO.
In Brazil (second time), there are no coloured regions.
In Germany, the coloured regions are
Schleswig-Holstein (SH) and Mecklenburg-Western Pomerania (MV), according to the states and their ISO codes.
In the Netherlands, the coloured regions are
South Holland (ZH), Utrecht (UT), and Limburg (LI), according to the official provinces and their ISO codes.
Now we have (more or less) a list of ISO codes. It remains to figure out what order to put them in and how to extract meaning from these sequences of letters and numbers.