Not sure how it gets into extra-cmake-modules but I saw the following tree on my system:
+---/nix/store/s8abxisr8d5m6mgyqmas52msjzvdc0dn-wireshark-cli-3.0.3.drv
| + [...]
| +---/nix/store/izi9ma2lqz7kppswhqkrdh1b98a8a853-extra-cmake-modules-5.58.0.drv
| | +---[...]
| | +---/nix/store/scgsmlabpvm6r31kps8p7yflwh17q7ns-hook.drv
| | +---/nix/store/9krlzvny65gdc8s7kpb6lkx8cd02c25b-default-builder.sh [...]
| | +---/nix/store/0iwik51jw5r1a2ffk4q5fmlpbqziwkvi-bash-4.4-p23.drv [...]
| | +---/nix/store/8af1a7lnk062h46lfs762pkzbyam5sb3-wrap-qt-apps-hook.sh
| | +---/nix/store/lsd5v3xzsskl14fpi4n4a851d7h1g7i3-qtbase-5.12.0.drv
[...]
cce6e9e7a1