Because my router doesn't have WiFi built in, I bought a Unifi Pro AP wireless access point for use at home. The device itself runs on a version of BusyBox, the preferred Linux distribution for embedded systems. A significant piece of software is required for administrative tasks, though – the UniFi Controller. Because it relies on MongoDB, I installed it on a virtual machine that I only spin up when necessary.
After logging into the access point and changing the password, I wanted to change the SSH port to something non-default. BusyBox uses DropBear for SSH, but directly editing these settings on the device doesn't work. The firmware reverts to the default settings with every reboot. Instead, Unifi has a more complicated way to make these changes. (To their credit, this is probably a useful setup for people managing a significant number of access points.)