Whats happening here

[Tumtitums]

Hello can anyone

tell me what the builders were doing here in relation to the brown layer with the air brock ? Im assuming its not a damp proof course and that its still wet cement ? Is the work complete ?? Thanks

 

[AC Power]

Looks to me it's a temporary block to form a light fixtures housing meant for "through-away" use. Try pulling it out with some needle-nose plyers. You might see the chassis to a light fixture beneath (some exterior stairwells have lights at the toe-kick (riser) for safety).