That activates manual "spin recovery mode". It is never used, and is prohibited in fact, aside from the FCF ground checks on a legacy Hornet (F/A-18A-D)....it dumps the leading edge flaps full down which is a specific test point. My understanding is that it was a relic of the flight test jets that never went away. The issue is that when SRM is engaged, it gives full stabilator authority and sort of bypasses the normal closed feedback loop of the flight control computers and FCS. So if you aren't actually in a spin, it could be real bad. With the switch guard down (in NORM rather than RCVY), there is still automatic SRM, which is activated above a certain AoA with a certain yaw rate and a few other things that are honestly pretty hard to hit all at once. But it gives you the "spin arrows" on the displays, showing which way to shove the stick, which in turn, is the pilot consent for SRM to engage the flight controls and do its thing. I've only been in a fully developed spin once, and the arrows went away about 2 seconds after I put the SRM control inputs in. Step 1 of our out of control flight boldface/memory items is "Controls - Release" which 99% of the time fixes everything unless you are doing something really hamfisted, or trying to go over the top/pure nose high without enough airspeed and a partial or full boot of rudder input........the way we intentionally spin it (which is a syllabus flight during initial training) is park the nose 90 deg nose high, and at about 100 knots indicated, you split the throttles, one in full afterburner, one at idle, and throw in full rudder, full aft stick in pro-spin direction, wait....wait.....wait some more, flop over, wait some more, wait more as it flops around and swaps ends, and then finally it starts a traditional spin.......there is lots of angry beeping and tones, and if you are lucky you see the spin arrows for a split second. This was not the case in the 1980s and most of the 1990s, where we had a couple nearly unrecoverable spin modes you could get into. But the software got fixed eventually.