On https://www.freebsd.org/doc/en_US.ISO8859-1/books/faq/ we state:
> Windows® and Mac OS® users may be interested in instead using TrueOS, a FreeBSD-based desktop distribution.
TrueOS is no longer a desktop distribution; that was split out into Project Trident, which is now moving to Void Linux. GhostBSD, MidnightBSD, and FuryBSD are possible replacements.
A commit references this bug:
Date: Mon Dec 9 20:18:23 UTC 2019
New revision: 53671
Remove TrueOS from the FAQ
Submitted by: emaste@
Patch by: carlavilla@
Approved by: bcr@
Differential Revision: https://reviews.freebsd.org/D22721
Fixed. I'll prepare a patch to remove all the references to TrueOS in the website and in the Handbook.