There is latest HTB (aka HTB3) code. You can download this tarball, unzip, patch kernel and recompile. You need also different tc tool (also different from one for HTB1/2). In tar you will find both patch and precompiled binary.
Latest (4.5.2002) code has enabled dump debug feature. That
means that if some suspicious condition happen it will dump
whole internal state into syslog under debug facility. Please
make sure that you log debug facility somewhere !
The lines I'm interested in are all assertions, warnings and
lines beginning "htb*".
For manual and other materials look here. Thanks in advance for your reports.