ATOMDB
2 0.0000
He
Helium
1s²

This is some front matter.

Level 1 → 2
Electron configuration 1s² → 1s¹ 2s¹
Energy above ground 0.0000 → 19.819
Quantum state
n L degeneracy parity
1 0 → 0 1 → 3 odd → even
Energy level data source 1993ADNDT..55...81S
Energy level data source 1995A&AS..109..125V → (null)

And this here would be some stuff for after the table