>> Second, you need the ability to recombine these functions into a brand new program when facing a new task – a program that models the task at hand. Program synthesis.

"Program synthesis" is here used in an entirely idiosyncratic manner, to mean "combining programs". Everyone else in CS and AI for the last many decades has used "Program Synthesis" to mean "generating a program that satisfies a specification".

Note that "synthesis" can legitimately be used to mean "combining". In Greek it translates literally to "putting [things] together": "Syn" (plus) "thesis" (place). But while generating programs by combining parts of other programs is an old-fashioned way to do Program Synthesis, in the standard sense, the end result is always desired to be a program. The LLMs used in the article to do what F. Chollet calls "Porgram Synthesis" generate no code.