These are useful for email events, and possibly some custom messages.

Every item in the user's user.xml file can be referenced with a "%user_<tag-name>%".  This is the first area it attempts to match with variables that start with "%user_".

Next it searches the user properties in memory about the current session:

User session properties in memory:
{{{
	%user_id%
	%user_number%
	%user_listen_ip_port%
	%user_listen_ip%
	%user_port%
	%user_ip%
	%user_protocol%
	%user_name%
	%user_current_password%
	%user_the_command%
	%user_the_command_data%
	%user_current_dir%
	%user_logged_in%
	%user_log%
	%user_failed_commands%
	%user_session_commands%
	%user_refresh_user%
	%user_stat%
	
	%user_dieing%
	%user_pasv_connect%
	%user_last_logged_command%
	%user_session_uploads%
	%user_session_downloads%
	
	%user_session_download_count%
	%user_session_upload_count%
	%user_macbinary_enabled%
	%user_list_zip_dir%
	%user_list_zip_file%
	%user_list_zip_only%
	%user_list_zip_app%
	%user_list_dot%
	%user_zlibLevel%
	
	%user_last_file_real_path%
	%user_last_file_name%
	%user_login_date_stamp%
	%user_login_date%
	%user_login_date_formatted%
	%user_termination_message%
	%user_file_transfer_mode%
	%user_modez%
	%user_dataSecure%
	%user_secureType%
	%user_friendly_quit%
	
	%user_last_port_string%
	%user_last_time_remaining%
	%user_last_action%
	%user_sfv%
	%user_pause_now%
	
	%user_new_pass1%
	%user_new_pass2%
	
	%user_PASV_port%
	%user_sending_file%
	%user_receiving_file%
	%user_listing_files%
	%user_pasv_guessing%
	%user_do_normal_list%
	%user_dont_write%
	%user_dont_read%
	%user_dont_log%
	%user_didDisconnect%
	%user_adminAllowed%
	%user_sscn_mode%
	
	%user_file_length%
	%user_current_loc%
	%user_start_transfer_time%
	%user_end_part_transfer_time%
	%user_overall_transfer_speed%
	%user_current_transfer_speed%
	%user_seconds_remaining%
	%user_start_transfer_byte_amount%
	%user_bytes_sent%
	%user_bytes_received%
	%user_ratio_bytes_sent%
	%user_ratio_bytes_received%
	%user_start_resume_loc%
	
	
	%user_secure%
	%user_explicit_ssl%
	%user_explicit_tls%
	%user_require_encryption%
	%user_login_date_stamp%
	%user_login_date%
	%user_login_date_formatted%
}}}

Overall server items:
{{{
	%beep%
	%server_time_date%
	%login_number%
	%users_connected%
	%user_password%
	%user_current_dir%
	%user_sessionid%
	%user_site_commands_text%
	%user_time_remaining%
	%user_paused%
	%user_bytes_remaining%
	%user_pasv_port%
	%user_ratio%
	%user_perm_ratio%
	%last_login_date_time%
	%last_login_ip%
	%last_login_user%
	%failed_logins%
	%successful_logins%
	%total_logins%
	%downloaded_files%
	%uploaded_files%
	%bytes_received_f%
	%bytes_sent_f%
	%total_bytes_f%
	%max_server_download_speed%
	%max_server_upload_speed%
	%bytes_received%
	%bytes_sent%
	%total_bytes%
	%current_server_downloading_count%
	%current_server_uploading_count%
	%max_users%
	%ip%
	%beep_connect%
	%deny_reserved_ports%
	%deny_fxp%
	%about_info_str%
	%version_info%
	%start_time%
	%thread_count%
	%free_memory%
}}}