Studying basic direct current circuits, I've come across the term inferred absolute zero temperature on computation of resistances that change due to temperature. Based on my readings, I understand it to be a predicted value as the word "inferred" means. It predicts the value of the absolute zero temperature based on using a segment of the graph that seems to have a linear slope through extending that line to where the temperature is zero.
Although that is my understanding, I decided to ask it in StackExchange because I've searched for an explicit definition of this term and no source has ever defined it in such a way. You have to go through a lesson of resistances changing by temperature, find the terminology and read the paragraph to get it. I mean, for such a common lesson I can't believe that I couldn't find any source that just defines the terminology in a friendly manner or even have a Wikipedia article that defines it as there it gets a little more clear and precise.
Can anyone confirm this concept for me and define it more explicitly? By explicity I mean that say that the term means this, and not focus on some other topic where I have to read and it is only implied and that the terminology is just put there.
I got the image from this website.
Is it also right to say that, resistance and temperature in actual testing do not have a clearly defined relationship? Then their relationship also looks like a curve where a segment in the middle seems to have a linear behavior, which is where the concept of getting the inferred absolute zero temperature came from? Why does the resistance temperature curve behave like that? It's just that for me it kind of feels convenient that the middle segment has a linear behavior.