That website is absolutely bogus. Maybe it's been set up to make people think they should be earning less than they are.
I just had a look at the median salary for median salary for a physician in Gothenburg and it comes up with $43k annual. I know for a fact that a full time general practitioner earns ~7k euro a month after working for a year and general practitioners are on the low end payscale of doctors. There is also not a lot of variation, because health is predominantly provided by the regional government. If people work in private practices they actually would earn more.
Looking at some of the other numbers all the ones I know about are around a factor of 1.5-2 too low.
I had a look at Oslo, and it's suggested median salary for a software Engineer was almost exactly the same as the average starting salary for a STEM master degree graduate in 2020 (https://www.tekna.no/lonn-og-arbeidsvilkar/lonnsstatistikk/b...).
That does not inspire confidence, but maybe they are better in other profession, or other cities.
You're talking about devs that are very good at negotiating and got one of the very few positions offered by a foreign corporate entity with very deep pockets.
https://teleport.org/cities/prague/salaries/
Quite obvious.