Looking into the current version of doc/latex/base/fntguide.pdf in
TeXLive, I see for example this:
\DeclareFontShape{OT1}{cmr}{m}{sl}{%
<<5-8>> sub * cmr/m/n
<<8>> cmsl8
<<9>> cmsl9
<<10>> <<10.95>> cmsl10
<<12>> <<14.4>> <<17.28>> <<20.74>> <<24.88>> cmsl12
}{}
Note the doubled `<<' and `>>'! This must be wrong...
Werner