Why does `nix develop` scrub `SSL_CERT_FILE` environment variable which confuses people when they use `cacert` expecting that it's setup hook should work.

[CMCDragonkai]

If you see:

nix/src/nix/develop.cc

Line 318 in a44ae8b

"SSL_CERT_FILE", // FIXME: only want to ignore /no-cert-file.crt

You can see that nix develop will remove SSL_CERT_FILE.

Why does it do this, in fact it even has a FIXME too.

Can this be fixed so that cacert package can actually work in nix develop shells?