(1) [ASCII] control character, Start of TeXt

(2) Structured TeXt - the markup language used e.g. when editing this Wiki (see [Formatting rules]). 

[CMcC] expalined in the [Tcl chatroom]:	"There are a lot of variants on STX, and there'll be a lot more, but they all share a couple of characteristics (e.g. significant blank lines, leading space for indenting, *, etc). Some people from Python are trying to come up with a canonical STX.  I'm tracking their work, and adapting it."

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