Comment by neobrain

Unstripped, perhaps?

    ls -lh /nix/store/63rdpgbzn7f1smh7688crcrpfsh833bb-zed-editor-0.199.10/bin/zeditor
    -r-xr-xr-x. 2 root root 3.2M Jan  1  1970 /nix/store/63rdpgbzn7f1smh7688crcrpfsh833bb-zed-editor-0.199.10/bin/zeditor

EDIT: Ah, it was too good to be true. The true binary is hidden in libexec/.zed-editor-wrapped :(

    ls -lh /nix/store/52smrb1z8r4n71zx50xagkcdrhlga4y5-zed-editor-0.207.4/libexec/.zed-editor-wrapped
    -r-xr-xr-x. 2 root root 337M Jan  1  1970 /nix/store/52smrb1z8r4n71zx50xagkcdrhlga4y5-zed-editor-0.207.4/libexec/.zed-editor-wrapped

Extra weight also comes from webrtc, which nixpkgs dynamically links. So yeah, it's quite a large binary indeed.