This stack exchange post state the following. Debian and RPM packages don't contain source code, only the compiled result. However, you can fetch the source packages - SRPMS, or the Debian description, patch, and original tarball. That’s it. You can only download file that are provided in url where target deb file is located. Which files will be provided? Only package maintainers can determine that. Therefore, there could be a scenario where no source codes are available for download.

Quoting “D-Bus integration in Emacs” 1, D-Bus is defined as followed D-Bus is an inter-process communication mechanism for applications residing on the same host. The communication is based on messages. Data in the messages is carried in a structured way, it is not just a byte stream. According to 1, name of client application is “a series of identifiers separated by dots”, but an application can install multiple objects under its name which are represents as path like syntax – separated by /.