Radiator_Thermostat_II Spec. v1.3 – TFW references meaning

[WIsbrecht]

There are a couple references to the following specifications in Radiator_Thermostat_II.md.
Which exact specifications are being referenced here? Where do I find them?
What does "TFW" stand for?

spec. v1.3 - TFW-048/049
Spec. v1.3. – TFW-045
Spec. 1.3 – TFW-059
spec. v1.3 - TFW-063
Spec. v1.3 – TFW-061