Caps Lock returns to a normal lock in the merged keyboard defaults
Caps Lock is a normal lock again, and compose moves to Shift plus Caps Lock, in pull request 14939, which David Heinemeier Hansson merged into quattro. The merge is not in version 4.0.4.
The merged option is named omarchy:shift_caps_compose. Caps Lock sends an ordinary lock. Shift plus Caps Lock starts a compose sequence, the kind that turns the following keys into one character, so the emoji sequence is Shift, Caps Lock, then m, then s. The pull request says Shift plus Caps Lock does not also toggle the lock.
A user who sets their own keyboard options in the Hyprland input file keeps that setting. Hyprland is the program that draws the windows. The merged manual drops the troubleshooting note that asked why Caps Lock was not working. Hansson wrote that on a US and Danish keyboard, Caps Lock toggled and the shifted key composed a smile.