How to read default keymaps.
Here is a typical default keymap display for an action:
|NVT||Ctrl-a + r|
If an entry is missing, then there is no key that maps to that action.
If a key has modifiers in front of it (Shift, Ctrl or Alt), it refers to those modifier keys pressed at the same time as the base key.
In more than one key is listed, separated by a +, it refers a multi-key sequence: pressing and releasing each key (or modifers and key) in sequence.
If more than one key is listed in a vertically-stacked list, it means there is more than one key mapped to that action.
For x3270, key names are listed as .
For c3270, key names are listed as or ordinary characters.