This value can be used to get or to set the scale of the currently assigned path for the instance, with a default value of 1. This is a scalar value, so 1 is a scale of 1:1, while setting it to 2, for example, will be double the scale and setting it to 0.5 would be halving the scale.
For functions relating to paths, see here.
Real (single precision floating point value)
path_scale = 1 + random(2);
The above code will set the current path's scale to a random size between 1 (its original size) and 3 (3 times its original size).