Edit ▸ Keyboard Shortcuts… (Ctrl+Alt+Shift+K) lists every shortcut. Menu commands show their shortcut next to their name. Help ▸ Keyboard Shortcuts opens the same list on the web: Keyboard Shortcuts.
Help ▸ Master Page Help (Ctrl+Shift+/ or F1) opens these pages in your browser. Help ▸ Open Sample Document opens a sample to try things on. Help ▸ Other Apps shows the other Rainbow Factory apps.
Help ▸ Send Feedback… sends a message, with screenshots if you like, straight to the developers; Send Feedback (Form)… opens the same message as a form. Window ▸ Feedback (Ctrl+Alt+F) keeps the feedback palette at hand while you work. Under every answer of the AI Console, Report this answer sends that answer to the developers.
Master Page is updated by Google Play, like your other apps; there is no Check for Updates command.