The Tools->Customize dialog (Tab Keyboard) has some entries greyed out. The help should mention why these entries are greyed out. https://help.libreoffice.org/7.6/en-US/text/shared/01/06140200.html
That makes sense. Something to add in the "Shortcut keys" section. Wasn't documented in OOo 3.3 either.
Now in the Shortcut keys section we have this text: ----- Shortcut keys Lists the shortcut keys and the associated commands. When inside this panel, use a shortcut key to quickly jump to it. ----- I could add a paragraph here, but I don't know why the key are grey out. @Samuel, @Stephane?