Generally, the entirety of the engine was developed to be modular. They could replace the compressor stage, add more stages, change the injection and burn stage, the turbine, the post combustion stage.
Initial papers from the 90s about the 9T thrust m88 did say that this would also require changes to the inlet of the plane itself, with swaps to the compressor and post combustion stages. It’s likely that they use a newer method for the T Rex tho.
As for the precise point you asked about, it’s only about the engine itself. Safran doesn’t make the airframe, they do however probably give required air intake specs that dassault then has to achieve with the airframe design
RBE2 appears to have 2 upgrades proposed. One with the same architecture but probably some form of GaN implementation starting with the later F4 standard, and one redesigned radar, the RBE2-XG, fully utilizing GaN and with multiple improvements such as detecting and jamming simultaneously, for F5 standard
Tried to put a post on dev server discussion regarding the addition of exocet and stuff if anyone cares to add to it. Exocet could be provided to Rafale if it were added. Sea Eagle is being added on Hawk according to news, so the argument against exocet from the prior rafale thread no longer stands.
There’s a report for the different ACM patterns of the rafale. Hopefully they’ll get implemented instead of copy pasting other modes as a generic stop gap.
