Features
Abaco supports most of the HTML 4.1 standard, including frames, tables and other tags.
More detailed information in the Wikipedia Page and the paper.
Screenshots
Source
Browse the source code online at Bell Labs or get it here. Plan9port version: abaco-p9p.tgz.
Binaries
Arch Linux i686 package: abaco-20080209-1-i686.pkg.tar.gz.
Optional Fonts
Antialiased FreeFonts: freefont.tgz.