Here my Dockerfile
create folder Downloads
COPY /plv8_v.2.x ./Downloads
RUN dpkg -i Downloads/plv8-96_2.1.0-2_amd64.deb
RUN dpkg -i Downloads/v8_220.127.116.11-26_amd64.deb
As you can see in Docker container install 2 deb files. OK.
But how I can understand that this 2 deb packages was success installed?
Maybe some logs or smt else?
You run a container from the image and use
dpkg -l | grep plv8 or whatever the package name is after installation.
You can also use
docker sbom YOURIMAGENAME
which will parse the image and list the found packages.
It is very unlikely though that the deb packages are not installed as it would return an error code and the build process would fail.