[ROCKLOBSTER]

That is related to sofware releases and how they are tracked - whole numbers indicate significant changes to the overall system while decimal releases indicate changes which may only be minor or at least do qualify as wholesale layout changes.

So, how does this apply to "My Pillow" or the Ford 5L V8?

multiple decimals such as 2.01.23 to indicate bug fixes and the like

Well, that all seems legit, when there's another number AFTER the "point oh".

[meyer]

In numbers, and not version numbers, the numbers to the right indicate the significant digits, the accuracy of the measurement. Or, well, they’re supposed to.

For example, you can say you have a 5 liter engine, even though it measures 4.67, merely by rounding off. Same as if you have a 5.2L engine, you can call it 5, but if you precisely measure the displacement, 4.67 or 5.2 in the 2 examples will tell you that not only is it that particular size of engine, but it is measured to a higher accuracy than 5.

Then again, ford called their old 302 a 5.0 despite it being 4.9 liters.

[stylin19a]

back in the day...the whole # was given to a major deliverable. Del. 2
when a bug release or an interim modification was needed, the decimal came into play Del 2.5

did or when did that change? who knows.