Ah, flood damage! (That keeps happening in our department.)
That crust is what happens when a big droplet of water sits on some power-supply pins: electrolysis destroys the metal, also making gas bubbles, until the water fills with conductive salts, then the heat from high current vaporizes the water and halts the process. It looks like your water-blob sat between the two chips, also getting underneath both. Even inside a plastic enclosure, condensed water from cold conditions can collect to form one big droplet.
Don't be surprised if some copper traces, (and even IC pins) are completely etched away. Beware: the corrosion might be full of heavy-metal salts from tin-lead solder used in older pcbs (yours looks too recent for that, but perhaps wear gloves, avoid licking fingers.)
8-pin chip, I find TC1301BSSA, dual LDO voltage regulator for under-6v supply, the "SS" means each one contains a pair of 1.5V outputs, see SMD marking list found at https://smd.yooneed.one/code4253.html