Hi,
Spaceskip glue with zero stretchability and shrinkability is not
marked as such in log when spacefactor is not 1000.
\spaceskip=1pt
\setbox0=\hbox{I turn}\showbox0
Output:
.\glue 1.0
Spacefactor does not change the glue (due to zero
stretchability and shrinkability), so output must be:
.\glue(\spaceskip) 1.0
Best,
Igor