defoldfonts
Restores the old LaTeX-2.09 font commands (\rm, \sf, \tt, …) that were dropped from the LaTeX kernel.
The package defines the old font commands \rm, \sf, \tt, \bf, \it,
and \sc, which were declared obsolete with LaTeX 2ε and have been removed
from the LaTeX kernel. It also defines the old KOMA-Script font command
\sfb.
This can be useful when using a class such as the KOMA-Script classes — which
do not define the old commands by default — together with an old BibTeX style
or BibTeX package that relies on them. It should however be considered a
workaround rather than a permanent solution. The recommended real solution is
to replace the obsolete commands with e.g. \rmfamily, \sffamily,
\ttfamily, \bfseries, \itshape, \scshape, or the corresponding text
commands taking an argument: \textrm, \textsf, \texttt, \textbf,
\textit, \textsc. These newer commands can also be combined or nested to
combine font attributes — something the old commands do not support.
The package is hosted on Codeberg. See the CTAN catalogue entry for more.