Mantis BT is available in several Linux distributions including: Debian, Ubuntu, Fedora, Gentoo, Frugalware and others.
Hence, if you are running Linux, start by checking if your distribution has a package for Mantis BT.
The query mutex becomes a very hot spot especially if you are using RBR.
In fact, with RBR there is a binlog event for each modified row, thus the mutex is acquired for every row.
Quickly ruled out were php*Something* names which, incidentally, although popular, do not seem to be condoned by the PHP Group developers.
However, over time the project was typically referred to as Mantis.
Kenzaburo Ito and a friend originally created a bug tracker as an internal tool for their pet project.
It is not recommended to use development releases in production specially if it is still in the alpha stage unless the administrator is familiar with PHP and is able to troubleshoot and fix any issues that may arise.
When initially seeking to name this project Ken ran into a problem every programmer encounters. It has to be descriptive, unique, and not too verbose.