Imagine you want to test some changes to a piece of software and already have an image you've built running on the target. You can set:
PACKAGE_FEED_URIS = "http://<ip-address>:8000" PRSERV_HOST = "localhost:0"
which sets up the image to refer to that package feed and ensures package versions increment.
Update the index with:
Start an http server with:
python3 -mhttp.server /path/to/deploy/rpms
Then you can do something like:
"bitbake <recipe> -C compile; bitbake package-index"
to cause recipe to recompile and then be available to update on the target using the package manager of choice (should work for opkg or dnf).