Hi,
I add this in user.filter,
CLIENT-HEADER-TAGGER: mytest Test
s/.*hel.*/MYTAG/
and this in user.action,
{+client-header-tagger{mytest}}
{+block{bl}}
TAG:MYTAG
I test it with command
curl -v  -H "User-Agent: hello"  -x  http://127.0.0.1:8118   www.bing.com
but it does not work. Privoxy version is 3.0.26.
Thanks.