Third party addons
Starting with 384.15, Asuswrt-Merlin now supports web integration for third party addons. Up to a maximum of five custom pages can be added at any location on the webui.
There is also a dedicated settings storage for addons, separate from nvram, and therefore not bound to its limitations (i.e. you can create new settings without having to recompile a firmware image).
The /jffs/addons/ directory is the standard location. You should create a directory there to store all your files.
The user-defined settings for all addons will be stored in /jffs/addons/custom_settings.txt.
The firmware supports up to five custom pages. These pages should be mounted at boot time through a script, which should ideally be called from services-start. You should put your custom page in the /jffs/addons/my_addon/ folder along with the install script. Here is a sample of an install script, which will also insert your page as a new tab in the Tools section.