I believe it's rp_blackmesa_complex, as stated in this addon's comment section somewhere. If I remember correctly, the origins of that area in specific would be the Half-Life mod "Residual Life", but I could be wrong.

It is in fact rp_blackmesa_complex, and the location used is from a few mods, it's most probably a common prefab that mappers use for locations. (Residual life loved using prefabs)