Basically means that the core OS files and systems can’t be changed. Everything else is stacked on top, and usually it means that you can rollback to a previous OS version if an update breaks something, without relying on any other image backup software.

Usually results a more stable reliable system, or at least one that’s easy to revert to working.

The downside being a reduction in flexibility and customizable options, and most programs need to be “containerized.”

Right? If you Google “twin towers” half of the pics are of it burning.

It’s just the most common search, especially in English because more English speaking countries only know the location because of the event.