dumpkeys writes, to the standard output, the current contents of the keyboard driver’s translation tables, in the format specified by keymaps(5) .
Using the various options, the format of the output can be controlled and also other information from the kernel and the programs dumpkeys(1) and loadkeys(1) can be obtained.
Keycode range supported by the kernel
This tells what values can be used after the keycode keyword in keytable files. See keymaps(5) for more information and the syntax of these files.Number of actions bindable to a key
This tells how many different actions a single key can output using various modifier keys. If the value is 16 for example, you can define up to 16 different actions to a key combined with modifiers. When the value is 16, the kernel probably knows about four modifier keys, which you can press in different combinations with the key to access all the bound actions.Ranges of action codes supported by the kernel
This item contains a list of action code ranges in hexadecimal notation. These are the values that can be used in the right hand side of a key definition, ie. the vv’s in a line
keycode xx = vv vv vv vv(see keymaps(5) for more information about the format of key definition lines). dumpkeys(1) and loadkeys(1) support a symbolic notation, which is preferable to the numeric one, as the action codes may vary from kernel to kernel while the symbolic names usually remain the same. However, the list of action code ranges can be used to determine, if the kernel actually supports all the symbols loadkeys(1) knows, or are there maybe some actions supported by the kernel that have no symbolic name in your loadkeys(1) program. To see this, you compare the range list with the action symbol list, see option --long-info below.
Number of function keys supported by kernel
This tells the number of action codes that can be used to output strings of characters. These action codes are traditionally bound to the various function and editing keys of the keyboard and are defined to send standard escape sequences. However, you can redefine these to send common command lines, email addresses or whatever you like. Especially if the number of this item is greater than the number of function and editing keys in your keyboard, you may have some "spare" action codes that you can bind to AltGr-letter combinations, for example, to send some useful strings. See loadkeys(1) for more details.Function strings
You can see you current function key definitions with the command
dumpkeys --funcs-only