What is the basename format for `/var/lib/apt/lists/*` files?

Given a /etc/apt/sources.list.d/foo.list file of the form

deb http://my-domain.tld/my-apt-repo mydistro mycomponent othercomponent

what kind of names can I expect for the associated files created by apt-get update?

There seems to be some transformation from apt repository URL to the basenames of the associated /var/lib/apt/lists/* files. Is this documented and, if so, where?