I saw a Russian electrician use a solder pot on Youtube. For some reason they seem to love having lots of junction boxes in inaccessible spaces, which is why they use some kind of maintenance-free, permanent connection like soldering or crimping. The Germans mostly did away with junction boxes in the 80s, making connections behind sockets and switches instead.
There's a VDE standard on wire nuts ("Drehklemmen"), VDE 0613-2-4 based on EN 60998, even though I'm not aware of wire nuts ever having been widely used over there. Occasionally stores aimed at DIYers sell them, including the famous supermarket centre aisles (some discount supermarkets have an entire aisle devoted to random non-food products, e.g. clothes, shoes and the strangest power tools, Aldi recently sold a mini excavator).