http://l3tczdiiwoo63iwxty4lhs6p7eaxop5micbn7vbliydgv63x5zrrrfyd.onion/3.0.34/user-manual/actions-file.html
Please refer to the filter file chapter to learn which client-header
filters are available by default, and how to create your own. Example usage (section): # Hide Tor exit notation in Host and Referer Headers
{+client-header-filter{hide-tor-exit-notation}}
/ 8.5.5. client-body-filter Typical use: Rewrite or remove client request body.