Time to time I come across fighter aircraft instrument panel photographic
images and find no red line limit on the airspeed indicator. What is the
policy and who puts the red line on the airspeed indicator? Do red line
speed change depending on aircraft loading? Do they rub it off for secrecy?
Is it done at the factory?

For example I have Bf109E photo instrument panel with red line at 400 kmh.
The specification for Bf109E doesn't tell you what the red line speed is.

Emilio.