There are some sort of minor utilities here that were constructed last year. I am not sure what they are, but they looked to be related to water although there's literally a shipping container here. This time, I saw a full/returning septic tank vehicle (i.e. asenizators) stop and turn into here. Last time there were a couple parked (although they might have been just pumping out during some sort of accident or something, I wasn't sure) https://www.mapillary.com/app/?pKey=1011577966716943&focus=photo . There is nothing beyond this point but a forest track/path, so I am guessing this might be a sewage access point for a vehicle like this. So may be a pump station with sewage access too. I didn't stop to check and there aren't any obvious signs.

How did you not figure this out from my note? 🙃