By default, Hv3 saves absolutely no data to the file system. After the Hv3 window has been closed, it is not possible for anyone else using the same computer to discover which websites you have visited or logged in to.
However, although this preserves your privacy, sometimes it is not conveniant. If a "state file" is enabled, Hv3 stores the following data to a file on disk:
To use a state file, specify the "-statefile" option as part of the command line used to start Hv3. The -statefile option is used to specify a file on disk used to persistently store various elements of the browser application state. Windows users may need to create a "batch file" to achieve this. For example, assuming that the Hv3 binary is named "hv3-linux-nightly-07_0723" and you wish to use the file "/home/dan/hv3_state.db" as the statefile, the full command line would be:
hv3-linux-nightly-07_0723 -statefile /home/dan/hv3_state.db
Because the state file is actually an SQLite database, there is no problem with two or more Hv3 processes using the same state file simultaneously. Bookmarked and configuration settings are propagated between instances automatically.
hv3_polipo is a very slightly modified version of the standard polipo program by Juliusz Chroboczek, available at http://www.pps.jussieu.fr/~jch/software/polipo/. The modifications are designed to make sure that no hv3_polipo processes are left running if hv3 crashes or is terminated by the operating system. The patch used to create the custom version is available here.
If building Hv3 from source code, you probably want to obtain hv3_polipo as well. The starkit and other pre-built packages available here already include pre-compiled versions.