its literally just a single perl script. i never made an rpm for it. i probably should eventually put it up on openrepos, with instructions on how to apply the patches you need to make lock screen work, and add a systemctl service to run it, and a billion other QoL things.
anyway, this is the direct link to the thing to download:
https://raw.githubusercontent.com/teleshoes/sf-button-monitor/refs/heads/master/src/sf-button-monitor