I wonder if I did something wrong but to me it looks like all of a sudden the Rule Engine Node as well as the String Manipulation Node are no longer part of the default installation of KNIME.
Could that be the case?
How did I discover this? I took an older workflow from 5.2.0 and opened it in 5.3.0 to find the message about missing extensions. When I further investigated, it looks like these two nodes (+ others??) are now part of the Java Snippet Extension, which is not installed by default, see here (Rule Engine – KNIME Community Hub)
Or did I somehow do a faulty installation of KNIME?
Thanks a lot @ArjenEX - through another conversation, I think I found out, this must have been a faulty installation. The thing is that it happened on multiple instances in our organization and therefore I concluded that something has changed. But it did not, at least not on the KNIME side.