Between versions 3.6.x and v4.7.x Tinderbox download DMGs included a copy of Yojimbo. This is a prize-winning clipping manager from BareBones software that can serve as Tinderbox's inbox (BareBones are the makers of BBEdit).
A full Yojimbo license was included with each new Tinderbox purchase or paid upgrade (presumably dating from v3.6.0 release, 4 Jan 07, onwards). Existing Tinderbox users wishing to use Yojimbo beyond its demo period will need to purchase a Yojimbo licence from Barebones or Eastgate. If in doubt about your TB/licensing, contact Eastgate directly.
There is no requirement to install Yojimbo in order to use Tinderbox, it is simply offered by Eastgate as an additional tool.
To install Yojimbo, mount the Tinderbox disk image and drag the Yojimbo icon into your applications folder.
For more on Yojimbo see the BareBones website's Yojimbo page.
New Yojimbo releases were included in the next subsequent Tinderbox release.
Bundling of Yojimbo is now discontinued.