In my experience they typically ask you questions about the experience you've listed on your CV. If you say you have experience working with AWS, then they might ask you something like "explain what a VPC is and why is it useful?". Other more general questions are usually along the lines of "tell me about a solution to a problem you solved and how you designed the solution to that problem".

The few times that I've been asked very specific technical questions they have always been related to the job I was applying for. Example: a ruby on rails job interview I was shown a few ActiveRecord models and asked what is wrong with them and how I would improve them - the answer was that they were all really polymorphic models but that was not how they were implemented in the code. Or for a frontend role, they might ask you "explain the javascript prototype chain to me".

Again, in my experience, its always seemed like the interview was more of a personal test rather than a technical one. Will the person be easy to work with? Will they be communicative or will they bottle up their issues and resent the team for it. Are they willing to learn? Will they be able to hande occasional pressure and stress? I think its generally accepted that its extremely difficult to accurately gauge a person's technical abilities in an interview. Also employees always start on a probationary contract in which they can be fired with 1-2 weeks notice, this usually lasts between 3-6 months, so if it turns out the employee was blagging it in the interview then it will become apparent pretty quickly and they will likely not make it past the probation period.

I have interviewed in the UK and did algorithm whiteboarding, so I'd say it's company-specific, rather than country-specific.

It's not much different in the UK if you apply to FAANG, hedge fund, or a cargo culting startup.