Include:AbuildRootBld

Install package abuild-rootbld:

apk add abuild-rootbld

Now you can build your source packages in an unprivileged sandbox based on bubblewrap with the command

abuild rootbld

If the build process needs network access there has to bet set the net option in APKBUILD.

There has to be done some additional configuration to use the rootbld sandbox in a Docker container.