[Termtools] Automatic pretty-printing of XTC files in Firefox?

[Frédéric Blanqui]

Hi.

I cannot remember what to do to have XTC files automatically 
pretty-printed in Firefox. For instance: 
https://www.starexec.org/starexec/services/benchmarks/7652799/contents?limit=-1 
. Could someone recall me what to do?

Frédéric.