As I’ve had to delete a blatant spam link it isn’t clear if this is a genuine post. Syntax highlighting was first introduced in v9.0.0 (Dec 2021), both a built-in method for Action Code (UI input boxes and notes using the Action built-in prototype).
Separately, the same version introduced user defined syntax highlighting got other formats.
A forum user, @Pete, has kindly contributed a BBEdit code-colouring configuration for Tinderbox Action Code—and just posted an update for the current Tinderbox v9.7.0 (see).
Whilst it might seem useful to have the same for Export code, any but the most trivial templates tend to mix action and export code adding to the identification of the type of code in that position. The Text/export pane does colour-code literal text vs evaluated export code vs included (transcluded) content which can also show how export code is working.