The HTML pages include a Google search box in the footer. Note that if using a local copy you must be online to use the search; Google will search the online pages—that might possibly be more recent than your own—and the search result links will likewise be to the online pages. If you have downloaded the TBX source, simply use Tinderbox's own Find tool to look for things.
Web engine search may be discontinued as we have no control over search engine crawlers and they are often slow to update small sites like this.
If reading the TBX source file, ignore the UTILS section which contains agents, prototypes, etc., used to create and maintain this file.