What is the package name of ubuntu installer

I would like to report a bug about the Ubuntu Installer. The problem is that it did not correctly installed the boot loader so that the newly installed system will not boot correctly without manual intervention. Details about the problem is asked at:

https://unix.stackexchange.com/questions/759555/how-to-fix-ubuntu-boot-problem-caused-by-previous-linux-installation?noredirect=1#comment1447746_759555

During the installation I was asked if I want to either: use the entire disk, install Ubutu along with my existing OS, or to manually partition the disk. I choose to partition manually, in order to keep all my files under /home.

I need help to either report this problem to the team, or tell me what is the package name for the installer so that I can report problem myself.

Thanks.