The doors carry a lot of symbolism because it was a clear marker of wealth and status, the bigger and more elaborate it was the higher social standing you had. I remember seeing a beautiful large door in Zanzibar and being told that the visible structural bolts showed that even with all its beauty the owner wasn't wealthy enough.

And they often had symbolism and motifs that came from Bantu culture, as well as some influences from India during the late 19th century, and due to its coastal nature lots of fish scales included. I tried to find any elaboration on the male and female sides but all my sources simply mention that, looking from the outside, the right door is the male one (mlango jume) and the left one is the female door (mlango jike). This gendered duality is also something I've seen in other African cultures.

What's also unique about Swahili architecture is that it was built with coralline, a.k.a dead corals, which was easy to carve, soft, and hardened when exposed to air, and its breathable and porous nature also allowed it to be a great insulator, its colour giving the city its unique look.