What is the property named, according to which a mathematical operation can be applied a multitude of times without changing the result beyond the first application? The simplest example of such a property could be multiplication by one, or calculating a number's absolute value repeatedly (e.g. abs(abs(X)) would return the same absolute value). The property essentially describes why a GET or DELETE requests can be retried, if you are familiar with these terms.
The answer to the previous question is "Fortran", last stable release in 2023. It is actively being used in supercomputers, in high-performance computing and according to their own words runs "close to the metal, fast". You can read more at https://fortran-lang.org/