If that pending transition is 1 Papryix logs some data, updates a cached transition to match, & zeroes out (via a helper) the transition settings, & indicates it should boot into UI mode.

Otherwise if it was 2 & it remembers which book you're reading (validating it still exists), Papyrix some similar logic but instead chooses Reader mode. Or it might do essentially the same if configured to & if it remembers you had a valid book open.

Otherwise it boots into UI mode.

2/2 Fin! Next: Mainloop!