Manual states incorrect box size when describing `\pgfsetfadingforcurrentpath`

I think that the pgfmanual v3.1.5 is not entirely correct when describing \pgfsetfadingforcurrentpath and \pgfsetfadingforcurrentpathstroked on p. 1202. It states that

Otherwise it is assumed that the fading has a size of 100bp times 100bp.

However, if one looks these functions up one finds in lines

pgf/tex/generic/pgf/basiclayer/pgfcoretransparency.code.tex

Lines 194 to 195 in 65bcaaf

	\pgf@xc=.02\pgf@xc%
	\pgf@yc=.02\pgf@yc%

and

pgf/tex/generic/pgf/basiclayer/pgfcoretransparency.code.tex

Lines 238 to 239 in 65bcaaf

	\pgf@xc=.02\pgf@xc%
	\pgf@yc=.02\pgf@yc%

So the actual box size is 50pt times 50pt (or 50bp times 50bp). This might be consistent with the statements on p. 1097 (if one replaces bp by pt).

Note that the claims here have been "empirically confirmed" in https://tex.stackexchange.com/a/546801/194703.

[hmenke]

To be honest, I don't really understand the low-level code here. I guess I have to research more. On a side note, 50 pt ≠ 50 bp.

@hmenke Yes, I know that 50bp is not precisely 50pt, just wanted to avoid comments saying I am too picky since they are very similar. The low-level code computes the width and height of the path picture, and finds a transformation that rescales a rectangle of width 50pt and height 50pt to the size of the path picture, and translates you to the center of the path picture (or however you want to call it). Imagine that before \pgf@xc=.02\pgf@xc the length \pgf@xc, which is then defined as the difference \pgf@pathmaxx-\pgf@pathminx, equals 50pt. After \pgf@xc=.02\pgf@xc we will have \pgf@xc=1pt, and the 11 entry of the transformation \pgftransformcm{\pgf@sys@tonumber{\pgf@xc}}{0}{0}{\pgf@sys@tonumber{\pgf@yc}}{\pgfpointorigin}% will be 1, so trivial. If the width is f*50pt, then 11 transformation matrix entry will be f. Likewise for the 22 entry, which rescales the y direction.