This file contains a big set of key bindings, one command for almost every key you have on your keyboard, prefixed by ESC. Here's the definition of the keys after pressing ESC:
A Prompts you for an away message, ENTER will un-away you.
C Shows you the /NAMES entry of your current channel.
D Shows the Who-list of people of your country.
E Prompts you for the launch of an external command with
/EXEC.
F Follows an invitation to a channel.
G "Greet" - Enter a query with the last person whose signon
has been detected by /notify.
H "Here" - Shows Who-list of users from your site.
I Invite the user who last sent you a message to the current
channel.
J Shows the WHOIS of the person who last joined your channel.
L List of channels with at least 3 persons on unless with
topic.
M "More" - Enter a query with the person you last sent a msg
to.
N Names list of public channels having at least 2 persons on.
O Who-list of operators online.
P Make your channel private.
Q Quit querying.
R "Reply" - Enter a query with the person who last sent you
a msg.
S Prompts you for a new server, ENTER gives a list of stored
ones.
T Prompts you for a topic for the current channel.
U Tells you how many users and servers are on IRC.
W Gives you the Who-list of the people on your channel.
X "eXamine" - WHOIS of the person who last sent you a message.
Y Toggles the SCROLL mode.
Z Toggles the HOLD_MODE.
, Flushes the server output.
TAB Clears the window.