So I create a container like this:
guix shell -C -F pango coreutils

Then in that container I do:
ls /lib
ls /lib64
The output is pretty long so I'd rather not send the entire thing, but
the issue is that it doesn't contain libpangocairo-1.0.so.0

When I do guix locate libpangocairo-1.0.so.0 I get:
pango@1.50.14
 /gnu/store/lj27gmzw22b2lcsfrs7lys5ygwp1hngl-pango-1.50.14/lib/libpangocairo-1.0.so.0
pango@1.48.10
 /gnu/store/p0ypxddznxfd7385c3q07q4cf17qghia-pango-1.48.10/lib/libpangocairo-1.0.so.0
pango-next@1.50.4
 /gnu/store/b86nbf0q1kkwicykl3a3wrrai6z2kd0i-pango-next-1.50.4/lib/libpangocairo-1.0.so.0

Which means that the file does exist and is part of pango, yet for some
reason it doesn't appear in the container.

Best regards,
Jan Libicher