After fetching dependencies for openssl, and building it, I've done
# dpkg -i *.deb
There are two more files:
libcrypto1.1-udeb_1.1.1d-0+deb10u6_i386.udeblibssl1.1-udeb_1.1.1d-0+deb10u6_i386.udeb
and they smell the same:

# file libssl1.1-udeb_1.1.1d-0+deb10u6_i386.udeb
libssl1.1-udeb_1.1.1d-0+deb10u6_i386.udeb: Debian binary package
(format 2.0)
suggesting they ought to be installed as well. But why the extra
'u'?I'm not too keen on shooting in the dark with root privileges,
soany light cast here would help lots.
Once that's OK, fetchmail will hopefully build.

Erik