Hello Woodpeck. 

Lojman in Turkish means “a house provided or given by an organization to its officials or workers for free or for a small rent.” “Kaymakamlık” is the administrative unit of a "ilçe"(may be translated ilçe=district, i am not sure) in Türkiye. “Kaymakamlık lojmanı” is the house allocated to district governors during their term of office. There are no signs outside these houses. These houses aren't government offices. They are just houses.

Many of this person's changes are about district governorship(in Turkish: kaymakamlık) buildings and district governorship houses(kaymakamlık lojmanı) in Türkiye. I asked Pelin Sungur, who I think is the same person, “what is the source of the district governorship houses you added”. https://resultmaps.neis-one.org/osm-discussion-comments?uid=22006507
But he didn't respond. 

I think that “Mehmet Bey”(user id=22152243) and “Pelin Sungur”(user id=22006507) are the same person. This person (or persons) has also attracted attention and was discussed in OpenStreetMap Türkiye Facebook group and OpenStreetMap Türkiye Telegram group. https://t.me/osm_tr/11798 

As far as I know, there is no public address and location information list of the district governorship houses(kaymakamlık lojmanı). The source of the information he added may not comply with OpenStreetMap's data license.

Have a nice day.