Timberwolfweb browser is the name of an ongoing project created to port the Firefox browser to the AmigaOS 4 platform. The Release Candidate 3 version was publicly made available to download on September 5, 2012.
It is called Timberwolf because it's not an official version of Firefox and not part of the main Firefox development repository, and because the name "Mozilla Firefox" is a registered trademark; along with the official Firefox logo.
TimberWolf was a bounty-funded project to port Mozilla Firefox to AmigaOS 4. It was started in early 2009 as parallel to AmiZilla, which had the same intent. AmiZilla had a more complex history, as it was started in 2003 from US firm DiscreetFX with the target of porting any running version of the Gecko engine based Firefox compatible browser to Amiga platforms. As AmiZilla was too ambitious, the project was closed on November 19, 2009 without producing significant results. Timberwolf was originally managed by Thomas and Hans-Joerg Frieden (AmigaOS 4 core developers).
The first release was made public in June 2010. On July 23, 2012, the project was declared completed and the money (€6732.72) was transferred to the Friedens.
At some point after the bounty was closed the Friedens ceased work on the project. In 2013 Steven Solie (AmigaOS 4 Team Lead) obtained the source code and began working on Timberwolf with an unspecified group of part time developers. 
The Amiga version of Timberwolf/Shiretoko/Firefox is based on XUL user-interface toolkit. The developers had to port a wrapper to XUL into Amiga, which was called XULRunner, in order to then port the whole Firefox to this platform.