Smart Key - Info Manuals

If pressed within an Info manual node:
  ACTION KEY
     (1) on the first line of an Info Menu Entry or Cross Reference, the
         referenced node is displayed;
     (2) on the Up, Next, or Previous entries of a Node Header (first
         line), the referenced node is displayed;
     (3) on the File entry of a Node Header (first line), the Top node
         within that file is displayed;
     (4) at the end of the current node, the next node is displayed
         (this descends subtrees if the function (Info-global-next)
         is bound);
     (5) anywhere else (e.g. at the end of a line), the current node
         is scrolled up a windowful.

  ASSIST KEY
     (1) on the first line of an Info Menu Entry or Cross Reference, the
         referenced node is displayed;
     (2) on the Up, Next, or Previous entries of a Node Header (first
         line), the last node in the history list is found;
     (3) on the File entry of a Node Header (first line), the DIR
         root-level node is found;
     (4) at the end of the current node, the previous node is displayed
         (this returns from subtrees if the function (Info-global-prev)
         is bound);
     (5) anywhere else (e.g. at the end of a line), the current node
         is scrolled down a windowful.

Use {s} within an Info manual to search for any concept that interests you.