You can customize the look of the prompts in the chat buffer. There are separate settings for local text (i.e. what you write) and foreign text (i.e. what other people write).
determine the faces used for chat messages.
determine the faces used for the prompts.
jabber-chat-foreign-prompt-format determine what text is
displayed in the prompts. They are format strings, with the following
special sequences defined:
jabber-chat-time-format defines how
%t shows time. Its
format is identical to that passed to
See Time Conversion.
jabber-chat-delayed-time-format is used instead of
jabber-chat-time-format for delayed messages (messages sent while
you were offline, or fetched from history). This way you can have short
timestamps everywhere except where you need long ones. You can always
see the complete timestamp in a tooltip by hovering over the prompt with
By default, timestamps are printed in the chat buffer every hour (at
“rare” times). This can be toggled with
jabber-print-rare-time. You can customize the displayed time by
jabber-rare-time-format. Rare timestamps will be printed
whenever time formatted by that format string would change.
You can also customize the header line of chat buffers, by modifying
jabber-chat-header-line-format. The format of
that variable is the same as that of
header-line-format. See Mode-Line Format. For MUC buffers,
jabber-muc-header-line-format is used instead.
jabber-chat-fill-long-lines controls whether long
lines in the chat buffer are wrapped.