/T-X-T-C-B-Y-I-N-T-T-X/
Yet another instance of hackerdom's peculiar attraction to mystical references -- a common humorous way of making exclusive statements about a class of things. The template is from the 'Tao te Ching'
"The Tao which can be spoken of is not the true Tao."
The implication is often that the X is a mystery accessible only to the enlightened.
See the trampoline entry for an example, and compare has the X nature.